Menopause & evolution

Interesting question:

Menopause means that the woman is infertile.

The older a woman when she has a baby, the more likely the baby will have a genetic issues, such as down syndrome. Menopause can be seen as a preventative measure against this happening. Women who did not have menopause and conceived a child later on would have a difficult time raising the child, and would most likely die as a result, not being able to spread their genes.

This is one idea, though there are also plenty more. For example, humans did not survive as long as they do today - I read somewhere that 40 was the maximum age most people would live to.