Assessing a patient’s tolerance for risk is important for any physician, and especially for surgeons, who take knives to things. Although the risks of life and limb are common discussions before surgery, I have recently been captivated by a very different kind of risk conversation that I’m having with patients: The risks of being an older dad. What’s an older dad? Most researchers agree that the term applies to men 40 years old and over.
Of course, you may not feel like you’d qualify as an older dad. But no matter how fit you are or how young you look, your genes are getting older – and they are changing. A review of the current research on sperm genetics (recently published by myself and a colleague) shows that as men age, so does the DNA in their sperm. And the older a man (and his sperm) gets, the greater the odds that these gene changes in his sperm could result in health problems for his offspring.
So what does the most recent research show? As men get older, their offspring will have increased risk of:
- Early (pre-term) birth
- Perinatal death
- Birth defects
- Chromosomal abnormalities
- Disease due to single gene mutations
- Childhood and adult diseases (i.e. autism, schizophrenia, bipolar, epilepsy)
If you’re over 40 and interested in becoming a dad (or having another child), that list probably sounds pretty scary. Let me clarify the risks a bit more with some perspective:
- The degree of risk increases with age. It’s never zero, but it remains low for some time before it shoots up. Think of a hockey stick laid on the floor. Grab the blade so it faces up and lift it up so that end of the stick is a couple of inches off the ground. That’s the shape of the risk curve with advanced paternal age. Pretty much flat until age 60 years and then a steep climb north after that.
- Human male fertility potential generally declines dramatically after age 70. Sperm production halts for good after that. Such is the rhythm of life. So, the men who carry the most paternal age risk are those who want to conceive after age 60 years and who are still making sperm.
- The conditions found in offspring of older dads are not really knowable ahead of time, as these issues are more subtle than the chromosomal issues associated with advanced female age.
- Although the relative risk (i.e. the risk over baseline) is several-fold higher in older men, the absolute risk is still quite small. For perspective, do you know the chances that a couple in the U.S. will have a child with a birth defect? I ask because this hardly comes up when couples are family building. It’s about 3-4%, give or take. And that’s about the same risk of schizophrenia or autism that an older Dad (>60 years) brings to his child.
- We still have much to learn about the risks associated with being an older dad – this field of study is just in its infancy (after all, until somewhat recently, humans typically didn’t live long enough to have kids after 40 years of age!). So, if you’re considering later-in-life fatherhood, keep having conversations with your doctor and keep an eye on the health news headlines for the latest developments.
The risk that comes with paternal age is very real, very personal, and very different than other kinds of risks in life. But the desire to be a dad at any age is as profound as any other on this good earth. That’s why this risk conversation with patients is as important as any other.