I came across an article on the web discussing evolutionary biology. The focus of the article was on fertility. Seems Mother Nature has only one aim at all times, propagate the species. In short, life must keep on going and that means babies. We have all heard this before. It's nothing new but what was new was the theory on the end of fertility:
If Mother Nature is so obsessed with babies, then why do females, at least the human ones, have an and to their fertility.
We know this moment as menopause.
Well, according to the article, it takes some twenty years or so for a human to reach full maturity. The author cites athletic performance as proof. Athletes start their peak performance some time in their early twenties and that is the starting point of physical and mental maturity. If it takes twenty plus years from birth to adulthood, then the parent must be able to live that long to care for the child.
No point having a baby in the last twenty years of your life as the baby would die when you die because you are not alive to take care of it. Therefore, female fertility ends some twenty years or so short of anticipated female life expectancy.
That's some theory, isn't it!
But, the article does not stop there. The article goes on to ask the question why does male fertility continue right up to the end of anticipated male life expectancy?
Before the answer is revealed, the article explains that males have a form of menopause, their fertility, sperm count, goes down. Much more significantly, males ability to achieve an erection goes down too. It's harder to impregnate a female if you can't get it up (my words), at least that's the story for human males.
Now for the answer to why male fertility continues until death. One word, mortality. Seems that males, the young ones in particular, tend to be aggressive, fearless, and fight each other to the death. We all know only too well the dumb behaviors of youthful males: drinking, drive by shootings, bungee jumping, a few wars, and so forth.
So, Mother Nature decided to keep male fertility going, just in case, all the young males in their prime do dumb things and kill themselves off. The old guys can step up and fill in the gap so to speak.
All I can say is I am impressed with the ability of the human mind to come up with very creative and incredible rationalizations to questions no one asked.
One more thing, don't believe everything you read on the web.