Wikipedia:Reference desk/Archives/Science/2014 May 20

= May 20 =

Efficacy of vaccines
If I got three different vaccines, let me say Gardasil, One against pneumonia, one against flu, in a time span of just 3 weeks, can that negatively affect the efficacy of vaccines? 112.198.90.97 (talk) 07:00, 20 May 2014 (UTC)
 * Sorry, questions calling for medical advice aren't allowed to be answered here. Please ask a doctor or pharmacist. --50.100.193.30 (talk) 07:25, 20 May 2014 (UTC)


 * We can't give medical advice, but we can direct you to information published in reliable sources. If you are really concerned about yourself, seek a medical professional. If you are interested in the general topic, here is a recent journal article titled "Long-term health effects of repeated exposure to multiple vaccines" . Here's another one titled "Simultaneous administration of childhood vaccines: an important public health policy that is safe and efficacious" . SemanticMantis (talk) 13:40, 20 May 2014 (UTC)

Identifying a bird
Hello. I found a wounded bird and have called the regional bird sanctuary to take care of it. In the meantime, can you help me identify what species it is? It comes from north-eastern Spain.

Picture of the bird.

Thank you! Leptictidium (mt) 07:22, 20 May 2014 (UTC)


 * A juvenile common starling, I think, but given that you're in Spain, it might be a juvenile spotless starling instead. 2.220.78.158 (talk) 08:14, 20 May 2014 (UTC)
 * I concur. http://2.bp.blogspot.com/-slZCKJpTRz0/UNZRTfwqfeI/AAAAAAAANVA/eQKRLw5eAwk/s400/Starlings+feeding.jpg 196.214.78.114 (talk) 09:44, 20 May 2014 (UTC)

Projectile dynamics
With no air resistance and perfect elasticity, the simplest approach would say that a ball thrown ahead without rotation on level ground will perform an endless sequence of identical parabolic arcs, but I feel that the degree of friction between ball and ground would have an effect on trajectories after the first arc. Is this so, and if so what would the effect be? What would happen in the limiting cases of the coefficient of friction being 0 or 1?→86.146.61.61 (talk) 12:38, 20 May 2014 (UTC)


 * The friction with the ground would induce more spin with each bounce, and accelerating the ball from no rotation or less rotation at each bounce would use up some of the forward momentum, so the parabolas would get narrower with each bounce, but remain just as high, given your assumptions, until the spin was such that the ball matched the ground, so rolled perfectly on it with each hit. Of course, in addition to being impossible in the real world, one set of your perfect assumptions are also inconsistent with each other.  If it was perfectly elastic, then it wouldn't deform at all when it hit, and would hit for an infinitely short period of time, and thus there would be no friction, either. StuRat (talk) 13:20, 20 May 2014 (UTC)
 * Perfect elasticity is the assumption, friction is a "feel" that the OP has. I'm not sure if perfect elasticity leads to zero friction, but if it does, then the solutions to the model would just be identical repeating parabolic arcs forever.
 * As for the claim that "perfect elastic, then it wouldn't deform" -- that depends on what OP means by perfectly elastic. E.g. if the modulus of elasticity is infinite, then no deformation occurs, and contact time (hence friction) is 0. But if the elastic limit is infinite, then even with a small elastic modulus, some sense of "perfect" elasticity is retained, even with positive contact time and friction. My impression is that "perfect elasticity" usually refers to the sense given at Elastic_collision, in which case, I agree that there is no friction, as that would fail to conserve kinetic energy. SemanticMantis (talk) 13:52, 20 May 2014 (UTC)


 * I actually meant by perfectly elastic that there was no loss of kinetic energy but that some compression was possible on impact - in which case, I would assume that in the case of non-unity coefficient of friction there was the possibility of momentary ground-contact sliding before the next parabola, which would certainly occur if the coefficient was zero, with the threshold value depending on the initial angle of projection.→86.146.61.61 (talk) 14:22, 20 May 2014 (UTC)


 * If we allow that the ball deforms, then the shape will continue to wobble back and forth into a variety of shapes until it hits the ground again - making the height of the second bounce harder to predict depending on whether or not the ball was already compressed along the vertical axis when it impacts that second time. If it's also spinning, then it's not necessarily a clean, symmetrical shape when it next impacts the ground - so the second bounce will launch it off at some angle that's crazily hard to predict.  You can see this in practice if you take a "super-ball" (which is extremely bouncy) and spin it as you drop it - the resulting motion looks chaotic.  The trouble is that deformation without energy absorbtion is impossible - and that makes talking about what happens rather difficult!  A zero here causes an infinity there! SteveBaker (talk) 16:55, 20 May 2014 (UTC)


 * However, in this idealized world, we can assume the ball would continue to move in the same horizontal direction, whereas, in the real world, a pebble it hit on one bounce might change it's heading entirely. StuRat (talk) 17:20, 20 May 2014 (UTC)


 * Chaotic? My experience with a "super-ball" as a child was that there was a predictable trajectory, with alternation (on a smooth level surface): depending on the initial spin and velocity vector, it might retrace a parabola back and forth (ignoring decay from energy loss), bounce along a zig-zag line, or do a short hop, long hop sequence. Without the energy loss, every second bounce would be essentially identical. —Quondum 01:27, 21 May 2014 (UTC)


 * "the parabolas would get narrower with each bounce, but remain just as high, given your assumptions" Assuming the angle of each bounce remains the same, and given that adding spin uses up kinetic energy as well as momentum, shouldn't we expect the height of each bounce to decrease (until the spin reaches maximum)? Olaf Davis (talk) 10:33, 21 May 2014 (UTC)


 * No, because only the horizontal component of the motion would be converted to rotational energy. Thus the angle would not remain the same.  Consider two tests, one with only vertical motion, which would never slow down, given the assumptions, and one with only horizontal motion, which would start out sliding on the ground but slow down and spin up, until it's spin made it roll on the ground.  Now combine those two motions together. StuRat (talk) 13:13, 21 May 2014 (UTC)


 * Yes, you're right of course. Thanks. Olaf Davis (talk) 15:12, 22 May 2014 (UTC)


 * You're quite welcome. StuRat (talk) 15:24, 22 May 2014 (UTC)

In the ideal case of no slip, you get a pattern that repeats itself with a period of 2 bounces. The ball initially without rotation starts to rotate after the first bounce and in after the next bounce that rotation vanishes. Count Iblis (talk) 14:35, 22 May 2014 (UTC)


 * Why ? StuRat (talk) 14:42, 22 May 2014 (UTC)


 * So, after the first bounce the ball rotates, and we want to find out what happens after the next bounce. Of course, anyone can write down the equations (conservation of kinetic energy right before and after the bounce and conservation of angular momentum w.r.t. the contact point) and solve the equations, but there is a much simpler way to see that the period is 2. You just invoke the fact that the laws of classical mechanics are invariant under time reversal and rotations. If the ball moves toward the right, it will start to rotate clockwise after the first bounce. The time reversed version of this is a ball that rotates counterclockwise and moves to the left which then bounces and loses its rotation. Since there is no dissipation in the no-slip limit, this is what would happen in the real world. Now a ball that moves along the x-axis to the left and rotates counterclockwise (angular momentum points in the negative y-direction) is transformed into a ball that moves to the right and rotates clockwise under a rotation of 180 degrees around the z-axis. So, under both a time reversal and a rotation, the motion stays invariant therefore, the ball will get back its original angular momentum after the second bounce. Count Iblis (talk) 10:33, 23 May 2014 (UTC)


 * I don't see it. What forces would stop the ball from rotating ?  If anyone can solve those equations, please show us your results. StuRat (talk) 19:44, 23 May 2014 (UTC)

Musical instruments
Why do people say it's harder to learn music instruments, the older you get? Isn't this true with any skill? Aren't all skills best learn when young, when the brain is at it's best? People say it applies more to musical instruments but I don't know why. Clover345 (talk) 15:05, 20 May 2014 (UTC)


 * The first thing that comes to my mind is time. Most people have more responsibilities when they are older, leaving less time to practice.  This applies to all skills, of course, but because so much of learning an instrument is muscle memory, without regular practice for months at a time (if not years) it is very difficult to do. OldTimeNESter (talk) 15:43, 20 May 2014 (UTC)


 * I doubt it's true of all skills, for example, I could imagine some skills that can only be learned once some other discipline is deeply understood and mastered - which might take a long time. Other skills only become fully matured after a lot of practice - so again, being young might make that impossible.  I'm sure it's true of many subjects - but I doubt that such a sweeping statement as "all skills" is justified.
 * I'm also skeptical of User:OldTimeNESter's claim that it's a matter of time. Older people who become unemployed and have to learn a new skill presumably have just as much time in school as a younger person...and retired people often take the opportunity to learn a new skill.  Certainly there are skills that are vastly easier to learn when young.  Notably, it's well known that a young child can learn new languages extremely easily - just by listening to people speak it in context...that's an almost impossible task for an adult. SteveBaker (talk) 16:38, 20 May 2014 (UTC)


 * I somewhat doubt the last statement. If I throw you into China, with no dictionary, no relatives, and no English anywhere, you might learn Chinese as quickly as a Chinese newborn.  When most adults try to learn a foreign language, they're still mostly working with their native language, which is hardly a fair comparison.  --Bowlhover (talk) 17:16, 20 May 2014 (UTC)


 * I believe the ability to learn things, from a neurological point of view, falls into the study of neuroplasticity. However, our article does not mention any aging effects on neuroplasticity.  However, there are lots of scholarly articles on the subject.  See  and  and  for a start, just some random articles I found.  -- Jayron  32  17:24, 20 May 2014 (UTC)


 * A decade or so ago it was quite noticeable in large public institutions that people older than 50 had trouble mastering new technology, in particular the Internet, and preferred to do things old fashioned way even if it was obviously inefficient. --AboutFace 22 (talk) 17:54, 20 May 2014 (UTC)
 * I think Bowhover's claim about language is clearly not correct. I immigrated from Poland to Australia with my parents when i was seven years old and picked up the language in about 12 months. 30 years later, my parents, as well as their remaining thick accent, are still not nearly as fluent in English as I am, even though they both work and have English speaking friends. There are definitely language milestones that you automatically reach at a young age which are either very difficult or impossible to achieve later in life. Actually I just found the article Second-language acquisition which discusses this, in particular the section called Comparisons with first-language acquisition. Vespine (talk) 23:36, 20 May 2014 (UTC)
 * To make the above not completely off topic, I believe there are parallels between learning language and music. Anyone can learn to play a few tunes on a musical instrument, but to become truly "fluent" I think you need to start early. Vespine (talk) 23:38, 20 May 2014 (UTC)
 * Heh. My ex-wife was born in Australia, but because her parents had arrived only 6 months earlier and spoke next to no English, they very wisely decided not to try to teach her their rotten English but let her assimilate the proper language when she started mixing with anglophone kids. So, her native language is Russian, but she started learning English from around 2-3 years, and that quickly picked up pace once she started school.  The upshot is that she is totally bilingual.  Her Russian is so good that she has appeared in Chekhov plays, she has coached Australian diplomats about to head off to a Moscow posting, and has been praised by Russian-born people for her eloquence (many have asked which area of Russia she was born in). Her English is so good that when she tells people she was born in Liverpool, they blithely assume she means Liverpool, UK, not Liverpool near Sydney. --   Jack of Oz   [pleasantries]  23:57, 20 May 2014 (UTC)


 * Clover, I notice that several responders above have correctly identified neuroplasticity as the root phenomena at work in how many skills ares best assimilated at an early age, but have not addressed the finer (and very fascinating) distinction you inquire about as to why the skill in question might be of the type that is especially easier to assimilate by younger learners.  The answer to that question lies with two forms of processing which the human brain excels at broadly, but which are constrained and specialized during childhood in a window known as the critical period -- auditory cognition and syntax.   Some of the earlier responders also quite correctly noted the link between the exercise of music and that of language; the two share some striking similarities in how the human brain processes them a sensory (and communicative) phenomena -- so much so that evolutionary psychologists and other cognitive scientists have been engaged in strong debate in recent decades in a chicken-and-egg style debate as to which one evolved to its current form first in our evolution into anatomically modern humans, as well as to how much they incorporate the same modules of the human brand and mind.  Putting aside the finer points of that debate though, it's clear that there is significant crossover in how music and language are constructed from discrete components (phenomena like notes in music and phonemes in language) which are combined to form structures which can impart complex meaning and sensation that often seem to be far more than the sum of their parts.


 * I know I've just thrown a lot of different terminology at you with minimal contextualization, so let me tie it all together a little better now. The reason I've addressed the issue incorporating language is that it is the much more heavily studied of the two phenomena in terms of neuroscience and cognitive science broadly (though neurological and psychological studies of music aren't exactly unheard of either), to we understand how the critical period works in language acquisition especially, and some of those lessons can be carried over.  One of the great revelations with regard to language in the last century was the formation of the concept of universal grammar -- the notion that all healthy human brains come complete at birth with a language organ that allows us to process language in (mostly) the same way as every other human.  However, the brain needs to be "fine-tuned" to the specific rules of the language spoken by those around the child, and this is where the critical period comes in; during this time the child begins to specifically internalize the various rules and distinctions that are the basis of their particular native language(s).   This includes a vast number of phenomena, but they can somewhat be divided into two groups -- phonology, the differences between the basic units of sound, and syntax, the rules for combining units of meaning together to make statements that other parties can comprehend.   So for example, as regards phonology, a child who grew up speaking only Japanese will have difficulty in making the distinction between "r" and "l" sounds in a language such as English, because their language does not have that distinction; to a certain degree, that will vary between individuals, they just simply will not be able to "hear" that difference, because the auditory-linguistic centers of their brain have already learned to filter it out while specializing on other distinctions that were more germane to their linguistic upbringing.  Likewise, word-order and other principles of grammar and syntax, will vary between their native tongue and any language they might try to learn later in life, and these rules are very much ingrained by adulthood as well.


 * Returning to the focus of your question, music shares many of these principles in common; it has specific sounds which the person who wishes to employ it must be able to distinguish between and produce reliably, and it has combinatorial rules which -- though experts are divided on calling syntax -- govern how these sounds are put together to form their intended meaning. In the context of music of course, the "meaning" is much more diffuse than it is in language -- more likely to instill a general emotional response than a concrete concept, but nevertheless, the order in which the sounds are combined and how they are stressed in relation to one another have a profound impact on how the effect those listening, as in language.  And also as in language, the earlier the exposure to these principles of the distinctions between sounds and how they are combined (including the motor control necessary for producing them), the better the chance that the learner will be able process and reproduce these distinctions with finer control.   It's worth noting, of course, that there are people who can become quite fluent in a language later in life and others who can learn a musical instrument with a fair degree of skill, but by and large, polyglots and musical virtuosos tend to be exposed to the relevant skills at a very early age.


 * I hope that answers your question in a basic fashion. I wrote the above in a bit of a hurry, so I hope its basically intelligible.  If you have more refined questions along these lines, don't hesitate to ask some follow-ups.   If you are interested in reading material along these lines which incorporate the relevant sciences (biological and social) but which are written for a very broad audience with no experience in those fields, I can strongly recommend Oliver Sachs' Musicophilia and Daniel Levitin's This is Your Brain on Music.  Both are quite informative without being too heavy in the technical sense and written more elegantly than any of the above.  S n o w  talk 23:10, 21 May 2014 (UTC)

Metric prefix
In Metric prefix it says "An exception is emission rates, which are typically on the order of Tg/yr."

Emission rates of what, where? Anyone know? -- SGBailey (talk) 15:27, 20 May 2014 (UTC)


 * Carbon emissions (sadly just a redirect to Greenhouse gas). There isn't a really standard unit for carbon uptake or emission. Two common ones from the ecosystem ecology and biogeochemistry fields are kg C/m^2/yr and Mg C/ha/yr. I've personally not seen terragrams actually used much, perhaps because the key fluxes in the global C cycle tend to be on the order of petagrams . As with all metric prefixes, scientists usually use the ones most appropriate for the scale of interest. So we might use kg C/m^2/yr for a forest or town while PgC/earth/yr for the planet. Altogether a weird mention, that doesn't add much. I might edit there a bit later. SemanticMantis (talk) 16:16, 20 May 2014 (UTC)

Gay parenting vs heterosexual parenting
I hope this is the right reference desk to ask this question.

Have there been any systematic studies that compare adults adopted as children by a same-sex couple with adults adopted as children by a heterosexual couple? By 'compare' I mean look at things like IQ, divorce rates, crime rates, rate of mental disorders, etc. I tried to find such a study with Google, but what I found instead was 1) studies which compare children adopted by homosexual parents with children raised by their biological parents, or 2) studies relying on parental self-reports of their children's well-being. 65.92.7.8 (talk) 18:10, 20 May 2014 (UTC)


 * Given that adoption by same-sex couples is a relatively new phenomenon in most countries (see LGBT adoption) I very much doubt that studies exist comparing divorce rates or crime rates for example - it is simply too soon for meaningful data to exist. AndyTheGrump (talk) 18:20, 20 May 2014 (UTC)


 * This study claims to have contacted and examined a significant number of "adult children of parents who have same-sex relationships". Unfortunately, the author does not compare them to adult children adopted by heterosexual parents, which is what I'm looking for. 65.92.7.8 (talk) 23:49, 20 May 2014 (UTC)
 * DeBoer v. Snyder has a list of the witnesses called by both sides, and a brief summary of their positions. They did cite actual research, so the article could be a good starting point towards finding those studies. K ati e R  (talk) 19:58, 20 May 2014 (UTC)


 * LGBT parenting. Short answer: the kids are okay. TenOfAllTrades(talk) 20:29, 20 May 2014 (UTC)


 * While there's certainly a consensus among academic psychologists that 'the kids are okay', I'm concerned about how this consensus was reached. For example, this study supports the claim that "[a]dopted children thrive in same-sex households" by using parental self-reports of whether their children conformed to "expected gender role behaviour", a method I don't consider to be rigorous or complete. If the consensus was formed from studies such as this, then I don't believe that the consensus is merited. IMO, the only legitimate way to determine whether children raised by a same-sex couple fare as well as children raised by a heterosexual couple is by directly comparing adults adopted as children by a same-sex couple with adults adopted as children by a heterosexual couple, and as far as I can tell such a comparison has not been made. 65.92.7.8 (talk) 23:49, 20 May 2014 (UTC)


 * See WP:NOTFORUM. This is a reference desk - we aren't going to engage in debate over the merits of adoption by same-sex couples, or over the validity of studies of adoption by same-sex couples. If you wish to engage in such debate, please do so elsewhere. AndyTheGrump (talk) 00:11, 21 May 2014 (UTC)


 * The OP has done nothing of the sort of "engaging in debate over the merits of adoption by same sex couples." As for questioning the validity of studies, he has only said it in reference to particular suggestions, to alert us that he is still looking for an answer to the question. I regard this as a perfectly reasonable approach, and can see no forum style debate - only an attempt to search for quality references. IBE (talk) 07:59, 21 May 2014 (UTC)


 * It is fortunate, then, that in the study you refer to (Farr, Forsell, and Patterson, 2010 PDF) the researchers made a point of collecting evaluations from teachers and outside caregivers, as well as from parents. The differences between evaluations by independent individuals and evaluations by parents were small, and not significant for either homosexual or heterosexual adoptive parents.  I get the impression, though, that you're going to keep moving the goalposts until you get the answer you want.  Per Andy, please go looking for debates elsewhere. TenOfAllTrades(talk) 00:58, 21 May 2014 (UTC)
 * Agreed. This is descending into a "help me selectively find proof of my preconceived notions"  We don't do that here.  The OP has been provided ample means to find the information they are looking for.  No need to keep this farce going any longer.  -- Jayron  32  01:40, 21 May 2014 (UTC)


 * I wasn't trying to enter a debate over same-sex adoption, and I'm not sure why Andy thought I was. Nor am I anti-same-sex adoption, as TenOfAllTrades suggests. My original question was, "have there been any systematic studies that compare adults adopted as children by a same-sex couple with adults adopted as children by a heterosexual couple", with the caveat that such comparisons use objective measures like IQ, divorce rates, etc. In reply, TenOfAllTrades directed me to the 'Children's Outcomes' section of the LGBT parenting article, which describes the consensus among academic psychologists that LGBT-adopted children fare no worse than hetersexual-adopted children. But this fact doesn't answer the OP, unless this consensus was formed by comparing adults adopted as children by a same-sex couple with adults adopted as children by a heterosexual couple with aforementioned objective measures (and I really hope it was). Admittedly, the study I mentioned before did better than rely exclusively on parental self-reports, but nonetheless I'm not exactly satisfied even with third-party subjective assessments.


 * Ultimately, I asked this question because comparing things like the IQ of same-sex adoptees with heterosexual adoptees should be both straightforward in principle and also the most objective way of assessing same-sex adoption, and I'm thus bewildered that such a study has not yet been done. 65.92.7.8 (talk) 01:55, 21 May 2014 (UTC)


 * Fair enough. But be aware that this is a charged topic, and people are likely to read subtext into your requests and comments, so choose your words carefully, with a mind to how they are likely to be understood.  -- Jayron  32  02:08, 21 May 2014 (UTC)


 * Thank you, and I'll pay closer attention to my wording from now on. 65.92.7.8 (talk) 02:17, 21 May 2014 (UTC)


 * Hmmm. I presume that you are aware that you're asking the impossible, or at least the extraordinarily difficult.  Same-sex marriages have only been legal – anywhere in the world – since 2001. 'Civil unions' for non-heterosexual couples haven't been around much longer.  It has been extraordinarily difficult for homosexual couples to adopt children under any circumstances until relatively recently; many otherwise-civilized countries (or states, within the U.S.) still actively discriminate against non-heterosexuals for the purposes of adoption.  Asking for outcomes for adult children – particularly of measures like divorce rate, which may require decades of adulthood to properly assess – isn't reasonable.  TenOfAllTrades(talk) 03:14, 21 May 2014 (UTC)


 * In Canada at least, same-sex adoption has been legal since 1985. It unfortunately took a lot longer for same-sex marriage to be legalized, but to my knowledge gay couples in a civil union have been able to adopt since at least 1985. I also know of at least one study that looked at adult children of homosexual couples, though the study in question was flawed because it compared children adopted by same-sex couples with children of heterosexual couples, not taking into account that children put up for adoption are not representative of the general population. 65.92.7.8 (talk) 04:42, 21 May 2014 (UTC)


 * Speaking specifically to Canada, those dates do not appear to be correct. The summary and timeline here is linked from our article, and seems pretty thorough.  The only thing that happened in 1985 was that Section 15 of the Charter of Rights came into effect, which eventually led to court decisions that expanded the rights of same-sex couples.  Legislative changes and court challenges that allowed same-sex couples to adopt trickled in beginning in the mid-1990s.  (Near as I can tell, British Columbia was the first province to legally recognize the right of same-sex couples to adopt, in 1996.)  The landmark decision came in 1999, with the Supreme Court's finding in M. v. H. that an Ontario law precluding same-sex couples from being considered common-law partners was unconstitutional.  This precipitated a massive number of legislative changes to bring an assortment of federal and provincial laws into compliance with the ruling.  (Even then, official discrimination against adoption by same-sex couples persisted in some parts of the country: .)
 * Incidentally, from your comment above I'm not sure that you were aware that a civil union is a specific, formally recognized relationship conferring many (or all) of the same rights as – or sometimes legally substituting for – marriage. (In some jurisdictions, a 'civil union' option for same-sex couples has been offered as a sort of 'separate but equal' or 'separate but nearly equal' option that avoids some of the emotional and political baggage of allowing same-sex 'marriage'.)  This is in contrast to a common-law partnership – which may have been what you were thinking of – which can be established without any paperwork, just by living together.  In any event, most of those court cases in the 1990s dealt with establishing that same-sex couples enjoyed the same right as opposite-sex couples to have their common-law partnerships recognized for various purposes (spousal benefits, eligibility to adopt, substitute decision-making for medical care, etc.).  In Canada it then required another six years – with the Civil Marriage Act in 2005 – before same-sex couples were allowed to marry.   TenOfAllTrades(talk) 13:00, 21 May 2014 (UTC)


 * Thank you for correcting me on the timeline of Canadian same-sex adoption, and yes I confused a civil union with common law partnership. 65.92.7.8 (talk) 18:56, 21 May 2014 (UTC)


 * It would be difficult to prove that IQ has anything to do with it. And a factor that I don't see mentioned here is where the adoptees come from. If the natural parents are troubled, it's not unreasonable to expect the adoptees to be troubled likewise, despite the best efforts of their adoptive parents. ←Baseball Bugs What's up, Doc? carrots→ 03:36, 21 May 2014 (UTC)


 * I think that you're absolutely correct about how troubled natural parents can lead to troubled children. A conservative study, which I cited above, tried to 'prove' that same-sex couples raise children more poorly by comparing adults brought-up by same-sex couple to adults with heterosexual parents, despite the fact that adopted children are unlikely to be representative of the general population. So it's not surprising that the study concluded that same-sex couples made worse parents than heterosexual couples. This is actually why I asked this question in the first place: the fairest way IMO of comparing same-sex couples with heterosexual couples is by looking at children adopted by heterosexuals, not children raised by heterosexuals in general. 65.92.7.8 (talk) 04:42, 21 May 2014 (UTC)
 * Yes, it's an apples and pomegranates comparison. Maybe you've heard the old saying, "Figures don't lie, but liars do figure." Also, those various "rates" are subjective. Kids from theoreticaly model families can end up as serial killers. One quantifiable figure (which Canada's data might go back far enough to provide) would be what proportional percent of adult homosexuals were raised by opposite-sex parents as opposed to same-sex parents. ←Baseball Bugs What's up, Doc? carrots→ 04:51, 21 May 2014 (UTC)
 * Why would that be an interesting figure? I would for example expect that bisexual or homosexual children raised by same-sex couples would be "out" much earlier and without much hassle, while children raised by opposite-sex couples would encounter the "usual" anxiety. There is no objective way to seperate sexuality from upbringing in an adult, IMHO. And another point to the discussion: Why would you even require IQ score (or some of the other measures mentioned above) to be equal? Is IQ suddenly a magically marker for "good upbringing"? Are children with lower IQ somehow "bad"? Remember, IQ does not equal general intelligence, and high IQ score (or intelligence) do not mean that you will lead a happier live or be more or less productive under all circumstances. These are really murky waters. Heterosexual couples are allowed to raise their children the way they want, why should homosexual couples have to conform to some form of "predescribed" upbringing? The children should not be actively harmed, in that I do agree, but that is a very different point than requiring "equal" upbringing. To clarify that point: No one is for example requiring the (heterosexual) Hillbillies to move into the Big City because the education there would be much better for their children. --TheMaster17 (talk) 14:30, 22 May 2014 (UTC)
 * And another thing I just realized: Would you find it really worrisome if gay parents would raise more gay children? After all, heterosexuals are also raising more heterosexual children at the moment. Neither of those is bad, or do you disagree? --TheMaster17 (talk) 14:32, 22 May 2014 (UTC)