New research suggests that overweight men are more likely to father sons, according to a study from the journal Fertility and Sterility.
The study, which looked at 8,500 couples who were in fertility treatments, found that slim men had 611 boys and 569 girls, while overweight men were 27 percent more likely to have sons, according to Metro.
“The present study is the first to report that overweight and obese men lead to a higher sex ratio at birth compared with normal weight men,” the study’s researchers said, according to Daily Mail.
Simon Fishel, a professor at the University of Salford and founder of CARE Fertility, told the Daily Mail that more research needs to be done “to confirm the results and to look at possible explanations.”
He did say one explanation may be that overweight men carry more Y chromosomes in their sperm, according to the Daily Mail.
Though the prospect of having a boy may sound intriguing for some couples, overweight dads could also pass on negative health effects.
For example, research from the University of South Wales found that obese children are more likely to be born to obese fathers, according to News.com. Specifically, the study found that grandsons of overweight grandfathers were more likely to be obese than grandsons of thinner grandfathers, according to news.com.
"The environment can change how our genes are expressed,” the study’s lead research, USW professor Margaret Morris, told news.com. “Pollutants, obesity, even stress can alter how genes are expressed in offspring without altering the genetic code.”
Similarly, Felicia Nowak, a researcher at Ohio University, said that some obese parents pass on traits that could influence their child’s weight, according to Psychology Today. She based this research of a 2013 study Ohio University conducted on the obesity patterns of mice, in which the mice were fed high-fat diets to become obese. The obese mice were more likely to birth obese children.
"We've identified a number of traits that may affect metabolism and behavior of offspring dependent on the pre-conception diet of the father,” Nowak said, according to Psychology Today.
This is why, as Psychology Today’s Christopher Bergland wrote, it’s better for parents, especially fathers, to be physically fit and healthy before conception to minimize risk of their child being obese.
Morris, of USW, said it may be best for soon-to-be dads to begin dieting three months before their wives get pregnant, according to news.com.
Thankfully for parents looking to conceive, there are diets and eating suggestions out there to help you cut down on weight before conception.
BabyCenter.com said parents planning to conceive should cut back on caffeine and high-mercury fish — both of which are also recommended for pregnant women after conception — to prepare themselves for pregnancy diets and to help them lose weight before giving birth.
BabyCenter also suggests soon-to-be parents cut back on processed, smoked and raw meats.
“While you're following a smart eating plan with low-fat, high-fiber foods, start or increase an exercise routine,” BabyCenter reported. “If you're overweight, aim to lose one to two pounds a week, a safe rate of weight loss. Extreme weight loss from crash dieting can deplete your body's nutritional stores, which isn't a good way to start a pregnancy."
For more pregnancy health tips:
Herb Scribner is a writer for Deseret News National. Send him an email at [email protected] or follow him on Twitter @herbscribner.