Recently, my dad has been dropping some not-so subtle hints and our conversations, over lunch or on the phone, have been following a certain formula:
“How’s work going?”
“It’s ok. I’ve been really busy with experiments.”
“I see. Is that why you’re dragging your feet on having kids?”
“Is there a Bruins game tonight”
“Yes, Dad, I’ll pick you up at 8 tonight.”
“Great. Would love to watch hockey with my grandkids someday.”
And even somtimes:
“Have you rescheduled my colonoscopy?”
“Yes. It’s for next Tuesday.”
“See? Who is going to do these things for you when get older, huh?
Despite his insistence, I try to tell him that it’s not that I don’t want children–I’m just not ready for children. For one, I’m not married. Two, I’m still in grad school making a pittance that barely supports myself, nevermind a family. Let’s face it, these figures aren’t exactly making a case for having kids either. And three, quite frankly, I’m just not ready to make that lifestyle adjustment.
My arguments, however, are never good enough for my dad. He often counters with a 1-2 punch consisting of a “who’s going to take care of you when you get older?” jab to throw me off guard and set me up for the ultimate guilt trip uppercut: “All I want is to hold my own grandchild. Then, I can close my eyes and die a happy man.” The first punch is a legitimate point seeing as how I am both his secretary and chaffeur when it comes to doctor’s appointments. And, admittedly, the thought has crossed my mind as to who would be driving me when it came time for my own colonoscopies. His second point, however, is one-part selfish and one-part low blow.
Then, last week I saw the following fortuitously-timed headlines: “Older Dads Have Healthier Kids?“(h/t
@LaurenAMichael) “Older dads may pass along a longer lifespan to their child.” And, “Kids of Older Fathers and Grandfathers May Inherit Longevity.” Seeing that Sunday would be Father’s day, I was excited to have new biological ammo to use against my dad.
Much to my disappointment, however, I was thwarted on two fronts. First, Father’s Day came and went without so much as a peep from my dad about the lack of grandkids, although, he might have been preoccupied with programming the clock on the microwave I had given him as a present. And second, a closer look at the reported research immediately tempered my excitement. In this study, researchers at Northwestern University found that the average length of telomeres, the tips of chromosomes, were longer in children of older fathers. They also found that this effect was cumulative, in that the telomeres were even longer in children if their fathers were themselves children of older fathers. The researchers point out that the increase in telomere length in children of older fathers is might be due to a known phenomenon where the telomeres in sperm cells increase with age.
With each cell division the ends of chromosomes are progressively shortened due to the peculiar inability of the enzymes responsible for DNA replication to do its job at the very tips of chromosomes. This is known as the End Replication Problem.
In order to protect chromosomes from deteriorating, an enzyme called telomerase “sews” to the end of chromosomes some “slack” DNA, which gets shortened instead, during cell division. Once telomeres reach a certain length it can signal to the cell to self-destruct through a process called apoptosis. For that reason, telomerase tends to be highly active in cells that are rapidly dividing since they are at the most risk for telomere shortening. Consistent with this, telomerase is very active in the testes (the site of sperm division), but how this might contribute to increasing rather than just maintaining telomere length is unknown.
While shortened telomeres have been linked to aging and age-related diseases, like cancer, and longer telomeres have been associated with longevity, this study did not examine any potential health benefits of older fathers bequeathing longer telomeres to their children. It is known, however, that as paternal age increases so does the risk of autism, schizophrenia, and other disorders in their children. Furthermore, the researchers were only able to measure the average length of telomeres. Since we inherit half of our chromosomes from our mothers and half from our fathers, its most likely that only the telomeres on the paternal chromosomes are longer.
After Father’s Day dinner with my dad, I went home and started thinking about how old he was when I was born. My dad was 46, making him one of many who followed an increasing trend (Table 21) of waiting to have kids. When I reflect back on my childhood, absent are those idyllic “father and son scenes” of playing catch with a baseball or tossing around a football. Or shooting hoops on a warm, Sunday afternoon– Ok, so maybe I’m guilty of employing a bit of “American-esque” dramatic license here, since I’m pretty damn sure my father’s never touched a baseball, football or basketball in his life. But my point is that he was sort of too old to do those things with me when I was a kid. That’s not to say he was a deadbeat, either. He was there for the spelling bees, the plays, the musicals (that’s right, I was a drama kid), and all of my hockey practices and games–but in the end, it just would have been nice to have been able to skate and pass the puck around with my Old Man. And when I start thinking about it that light, for a brief moment, it makes me want to have kids sooner rather than later.
Nobel Prize Press Release “How chromosomes are protected by telomeres and the enzyme telomerase“
Telome Health of Menlo Park tests age of DNA (I think they mean nucleotides and not amino acids.)