Wikipedia:Reference desk/Archives/Miscellaneous/2017 March 10

= March 10 =

Multiple sexual partners?
So hypothetically, a woman has unprotected vaginal sex with several men. My question is what factors would determine which man would likely be the father to the child. Let's assume the woman the woman does end up pregnant in keeping with the question. Also, all the men had normal fertility. Would say, sperm count/competition be the most crucial aspect? OR what? --  20:37, 10 March 2017‎ (UTC)
 * Motility could well figure into it. ←Baseball Bugs What's up, Doc? carrots→ 20:47, 10 March 2017 (UTC)
 * Fertility says that the age of the man matters for sperm count (so "normal fertility" varies). Advantage to the younger man.
 * Also, different men of the same age can have different sperm counts while still having "normal fertility".
 * I would think there would be an advantage to the man who had sex at the time of the woman's monthly peak fertility, which is from 5 days before to 1 or 2 days after ovulation. (See Menstrual cycle.)
 * Controlling for the above, is there an advantage to the man who was first (or maybe last)? It seems that I've read about that for non-human animals, but I can't recall where. Loraof (talk) 21:39, 10 March 2017 (UTC)
 * You may be thinking of a mating plug. Our article sperm competition is also of relevance to the OP.  CodeTalker (talk) 21:48, 10 March 2017 (UTC)
 * It has been suggested that the shape of the human penis evolved to displace previously deposited semen. Matt Deres (talk) 04:26, 11 March 2017 (UTC)
 * "Whoever gets there firstest with the mostest"? (misquote alert) Clarityfiend (talk) 00:02, 13 March 2017 (UTC)


 * In humans, the last to mate has the best chance of fathering a child. Abductive  (reasoning) 20:07, 14 March 2017 (UTC)
 * Citation, or at least reasoning, needed. —Tamfang (talk) 07:55, 15 March 2017 (UTC)
 * Dixson, AF, Human sperm competition, Human penis. Abductive  (reasoning) 22:21, 15 March 2017 (UTC)