Has crooked legs become genetic in Japan?

Question:

I love going to Japan. I go there every year or 2 since I was 10. But 2 weeks ago, I was in Japan and discovered something I never noticed before: 80% of Japanese girls that I saw had crooked legs and 40% of Japanese boys did too. I heard that is was because of the traditional way of sitting down in Japan, which was sitting on your knees. Not many girls in Japan sit like that anymore unless they're wearing a kimono. But normally boys wouldn't sit like that, and they would tend to sit in a lotus position, which normally makes your legs straight. So I'm thinking, since the Japanese women sat on their knees for such a long time during the period where they mainly wore kimonos, it may have become genetic and even spread the "crooked-leg gene" to the men too? I don't know if this sounds silly to anyone else, but is it true?

Answer:

Injuries that happen to you do not impact your DNA.
If your mother loses her leg to diabetes and then gives birth to you, you will not be born missing a leg. And it's not because your father still has his two legs and you got lucky.
Long ago a scientist thinking that things like this only come after generations of body abuse took rats and cut off their tails. And their offspring's tails. And their offspring's offspring's tails. You can see where this is going. He did this for litter after litter after litter but--guess what--all the rats were always born with tails.

Bowlegged-ness isn't caused by any style of sitting or nutrition. It's caused simply by genetics. Crooked legs appear in all countries, but the Japanese "bred" it into themselves. Long ago the walking style that gets created by crooked legs on a woman wearing a kimono was seen as more attractive. Attractive people are more likely to marry and have children as they were favored over others, and since this is a genetic defect where people are naturally born with a more starkly curved tibia bone in the leg the genes get passed down and continue.
The same goes with rats. Take a black-eyed rat and one with red eyes and the genes are going to be passed down. If you keep choosing to breed only the rats that display red eyes or carry the gene for it you're soon going to have a lot of red-eyed rats.