The much maligned egg of a woman over 35. It’s been the target of criticism for so many years that most women can easily rattle off their chances of a having a down syndrome baby in relationship to their age. (1 in 2000 for a twenty-year-old, 1 in 100 for a forty-year-old.) But now the research lens is finally aimed at male fertility and viable sperm. Turns out, men need to consider their fertility window too.
In the last few decades there has been a huge increase in the numbers of older men fathering babies. In the 35-49 age group, in particular, there has been a 40% increase of new fathers. Delaying fatherhood to play the mating field may now have intergenerational consequences.
A US study, published in Proceedings of the National Academy of Sciences, “Advancing age has differential effects on DNA change, chromatin integrity, gene mutations, and aneuplodies (chromosome abnormalities) in sperm” has shown that older men have higher chances of passing down genetic issues to their offspring. A French study backed up that finding, showing that infertility issues of men do indeed rise significantly after the age of 40.
Not only men who are waiting to have kids after the age of forty face fertility issues, but when they do successfully impregnate a woman, they have a higher chance of passing two specific gene disorders: schizophrenia and achondroplasia (commonly known as dwarfism.) The authors of the study, Andrew Wyrobek from Lawrence Livermore National Laboratory, and Brenda Eskenazi from the University of California, School of Public Health, blamed the quality of a man’s sperm, which they say, quickly weakens after the age of 40.
Women who are holding out for an older, more successful man, might consider this. One study found that women, regardless of their age, who carry offspring of a man past forty. increase their risk of miscarriage.
Finally, one other US study gathered and examined ninety- seven samples of semen, all coming from men from the age range 22-80, who were not smokers. When looking over the samples, researchers found that the activeness and the movement of the sperm related with DNA fragmentation. The study concluded as well that not only do women have a biological clock, but so do men.
With research like this, suddenly the idea of being young enough to throw a ball with a child becomes less important than simply being young enough to father a healthy child.