Why do most women get their first period around age 12 when their bodies are usually not well developed enough to safely carry a baby to term?

Question

Why do most women get their first period around age 12 when their bodies are usually not well developed enough to safely carry a baby to term?

In: 12558

Answer 1

Evolution doesn’t need to make ethical or rational sense, and usually doesn’t. You’re not looking at the steady, unstoppable march of progress. You’re looking at “eh, good enough” times a few hundred million. It overcorrects, it undercorrects, it fails, *a lot*. Species go extinct, and your existence right now owes less to your indomitable genetic superiority and more to the fact that, with an incomprehensibly large number of us, there is plenty of room for a whole lot of people, you included, to get lucky that “good enough for another generation” worked in your favor.

All “evolution” strictly requires is that *one* of a mother-child pair survive birthing. A surviving child is another generation. A surviving mother can typically try again. Our individual histories could be littered with a lot of young mothers dead way before their time, and our long-term species legacy certainly is, but it still gets us here, not because we are “strong” or “fit” but because our ancestors happened to just barely survive whatever happened to them.

So all that being said, the age at which women *can* become pregnant and, on the whole, either she *or* the child survives the experience, is a whole lot lower than the age at which they can both share the experience “safely.”