How does a man’s age affect fertility?
As men age, they don’t lose their fertility in the same way that women do. So as women go through that age range between 35 and 42, their fertility is essentially lost. In the case of males, fertility certainly decreases with age; that’s definitely true. But they don’t lose their fertility entirely. It may make a few percentage points difference in the likelihood of conception. But very few men are infertile because of their age; they will be subfertile because of their age.
Impact of father’s age on child’s health
The impact of the male age on the health of the offspring is very important. So as men get older, they don’t stop producing spermatozoa. But the quality of the spermatozoa definitely deteriorates with male age and the incidence of diseases in the children increases quite rapidly with male age. So we’ve known for many years that dominant genetic disease increases exponentially with the age of the father. But in recent years we have become aware that a whole range of neurological conditions, like autism, bipolar disease, spontaneous schizophrenia, epilepsy – all these are correlated with the age of the father at the moment of conception.
When does men’s sperm quality start to decline?
The inflection point, the age where things start to rise quite dramatically is around the age of 35. And interestingly enough it is the same age which woman’s fertility begins to get lost. We are the only primate species that stop reproducing in midlife. And it is as if we were only really designed or evolved to reproduce up until out of mid-thirties, maybe forty at the maximum. And after that, our fertility as a species is lost. So that there have been some studies done, where the side of a content of women and the content of men have been looked at as a couple.
The combination of a man’s age and a woman’s age
If the woman is below the age of 35, so she’s in her most fertile years, then having a male partner the same age as you or five years older makes no difference at all. But if the woman is on that slope to age-dependent infertility between 35 and 40 then having a male partner who is five years or more older than you makes a bigger ten percent difference in your chances of conception. So it is an aging couple in the way of the perfect storm, the female partner and the male partner are both losing their fertility with time. And it is important that we look at the couple, fertility is being a function of the couple rather than individuals.
Women, age, and fertility
I think there is a public misconception that the loss of female fertility is somehow synchronized with the menopause. And people imagine that they’re fertile until the menopauseб when in reality fertility has lost a decade before the menopause is hit. So it is very important that men understand that the fertility of their female partner will be lost rapidly in that age range between 35 and 42 and delaying having your family until the late thirties could be a very risky strategy.