Friday, December 08, 2006

Gender as Genetic

While talking with my coworker about family and genealogy, she uttered the phrase "boys run in the family" in reference to her fiance's dad and uncles having sons almost exclusively. I laughed at her at first, thinking her assertion that sex is genetic was ludicrous.

But as I thought about it more, I wondered, is one's sex genetic? I know that sex is determined from the male's sperm, without any input from the female's egg. But is the tendency to manufacture more male-producing sperm a genetic trait? Or are my coworkers soon-to-be in-laws just a statistical anomaly?


  1. Pls research this and find out, okay? :)

    My gparents had six sons and one daughter. Of their grandkids, a vast majority are boys (I'd say about 2:1 and we're talking about 30+ cousins).

    It seems that males run in our family too. I've never known if it was something in my gpa's sperm or if it was just random and then even more random that all his sons had sons too.


  2. I'll see what I can find, hb.

  3. The key to this answer is the Ph and integrity of the female's cervix. The theory is that what sperm fertilizes the egg depends on how viscous, or "sticky", the mucus in a woman's cervix is. The stickier it is, the harder it is for any sperm to get through. While the female or Y bearing sperm are lighter, and swim faster, the male or X bearing sperm are swim slower but live considerabley longer. Tenacious buggers!

    Women whose cervical mucus is relatively viscous would have a higher probability of male offspring and the the Y bearing or female sperm can't make it to the finish line. This may explain why there is a higher chance, in some famalies to have boys."

  4. Okay, so my spelling is awful...I get so intent on the content, I forget to review the post...arghhhh!


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