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Sperm competion with females and conception

A new chemical treatment that can segregate male and female sperm could one day mean parents going through IVF could choose whether they have a boy or girl. Scientists discovered the sperm with the X chromosome which gives rise to females slowed down when when a certain chemical was added while sperm with the male Y chromosome sped up. In experiments with mice sperm, scientists found they could produce litters that were 90 per cent male, according to the study published in Plos Biology. When the slower sperm were used, litters were 81 per cent female. The X chromosome has many genes while the shorter male Y chromosome has fewer, and this difference in gene expression meant scientists could distinguish between the two.
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Implications of diversity in sperm size and function for sperm competition and fertility

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Sperm Competition in Humans: Mate Guarding Behavior Negatively Correlates with Ejaculate Quality

Swipe left. In females, for example, hormones present at ovulation can drive a woman to choose a cocky, confident man with a slight stubble and more masculine features. Men can sniff out an ovulating woman just by smelling her T-shirt , while women appear to prefer the smell of a man with dissimilar genes , which could give her offspring a boost up the evolutionary ladder. A fascinating new study finds those chemical-based preferences continue even after sex. Human eggs appear to "choose" which sperm will become the lucky winner in conceiving a baby. And here's the extraordinary finding: A woman's egg doesn't always agree with her choice of partner.
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Why Are 250 Million Sperm Cells Released During Sex?

I don't make this stuff up, promise. I just find it and pass it along for your perusal: "Males may alter the velocity of sperm they allocate to copulations by strategically firing their left and right ejaculatory ducts, which can operate independently. Among red junglefowl, it's attractive females that do the trick, according to an article at Discovery. Similar sperm-control mechanisms have been uncovered previously. In fact, " sperm competition " is a well-supported idea that goes way back.
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When it comes to mating and determining whose sperm reaches the elusive egg, females control both the playing field and the rules of the game, according to a new study on male sperm competition vs. Miller, a postdoctoral research associate at SU. Until now, we didn't know why. Our study shows that it's because of female choice.
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Comments (10)

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