Run for the girls

I recently came across this piece from Runner's World:

When Isla Lough was born, the bookies offered odds of 100-1 that the daughter of the marathon world-record holder Paula Radcliffe would one day win the Flora London Marathon. A safer bet would have been to predict that Radcliffe would give birth to a daughter. For this you can "blame" her husband.

Research suggests that male runners who cover more than 30 miles a week – as Radcliffe’s husband and training partner Gary Lough does – are more likely to father female offspring. Researchers at the University of Glasgow divided 139 male runners into three categories: those who were taking a break from running when they and their partner conceived; those who were running less than 30 miles a week when their partner conceived; and those who were running between 30 and 50 miles a week when their partner conceived.

The study revealed that the non-runners and those covering less than 30 miles a week had a 62 per cent chance of fathering male offspring – compared to the average of 51 per cent for the general population. It was a dramatically different story for the runners covering more than 30 miles a week though: only 40 per cent of their babies were boys. The researchers put this trend down to the dip in the male hormone testosterone that occurs as a result of higher running mileage.

Running might affect the sex of your children, but it might also help you conceive in the first place. "Men who run regularly and stay at a healthy weight are more likely to maintain a good sperm count than men who are obese," says Dr Roger Henderson, a GP and marathon runner. Henderson does issue one warning: "Male marathon runners do not appear to have reduced sperm counts, although exercise that consistently heats the testicles, or which requires very tight-fitting shorts, such as cycling, may not help."

(Just for fun, I looked up the bio of Haile Gebrselassie, widely regarded as the best distance runner of our time. Turns out he has four kids: three girls and one boy. Then I checked Meb Keflezighi, another distance superstar and winner of last year's New York City Marathon: two daughters, and a third one is on the way.)

I don't know whether our +1 is a boy or a girl, and neither Zdenek nor I really care one way or the other. But it's interesting to note that we were at the peak of our marathon training and running well over 40 miles per week when the +1 first came into existence. (More importantly, we hadn't yet transitioned into our "very tight-fitting" cycling shorts, either!)