When's the best time to have a baby?
As many couples know, there may never be a perfect time, but medically speaking, at least, it's generally known that when it comes to being pregnant and giving birth, younger is better. After age 35 or so, women run greater risks of giving birth pre-term and dealing with other complications.
What about guys? It's generally been thought that when it comes to fertility, men have a free pass. Whether you're 25 or 75, it was previously thought that men were good to go. However, several studies suggest that the fertility clock ticks for men, too.
Male bodies constantly produce new sperm. Theoretically, at least, sperm produced by a body in its 50s, 60s, or 70s is just as capable of fertilizing an egg as sperm produced by a younger body. However, the ability of sperm to move, called motility, declines with age. Plus, the cells that make sperm are constantly dividing. As men age, and their sperm-producing cells continue to divide, there's a greater chance that their sperm will carry chromosomal defects and harbor mutated genes that can cause diseases and birth defects.
One study found that men who had children at age 40 or older were over five times as likely to have a child with autism. The risk of having a child with schizophrenia was doubled among fathers in their late 40's, according to another study.
This doesn't mean that all children born to men over 40 will have problems, but it does suggest that men haven't been left off the hook when it comes to keeping track of the biological clock.