When we talk about the health risks of obesity, we normally hear about diabetes, heart disease, and hypertension. But there’s another risk that deserves more attention because it affects what many of us value most: family. How much you weigh may have a major impact on your ability to reproduce. Excess fat can lead to infertility in both women and men.

One out of every eight women encounters fertility problems, and those who are obese face a far greater challenge. A year-long study published in the journal Human Reproduction found a strong relationship between a woman’s body mass index (BMI) and infertility. Researchers found that women who were severely obese (BMI of 40 or more) were 43 percent less likely to achieve pregnancy than normal-weight women. In addition, obese women with a BMI of 35 or more were 26 percent less likely to conceive. And considering that many women are now choosing to have children at later ages, which presents fertility challenges on its own, the importance of weight management takes on a whole new meaning.

Along with conception problems, obesity increases obstacles to a safe full-term delivery. Obese women have higher rates of pregnancy loss. Obesity also increases health risks for the baby. Research suggests that being obese during pregnancy may increase the risk of childhood obesity as well as diabetes or heart disease later on in life as an adult.

Obesity was once thought of as a problem for women trying to have children, but studies have shown a strong relationship between weight and infertility in men. According to research published in the journal Archives of Internal Medicine, obese men are 42 percent more likely to have low sperm counts and 81 percent more likely to be sterile than men of normal weight. The study also found that for every 20-pound increase in a man’s weight, there is a 10 percent increase in the chance of infertility.

The obesity epidemic affecting millions of Americans is largely related to diet. Researchers from Harvard found a relationship between fat intake and male fertility. In a year-long study of 100 obese and overweight men, eating a lot of saturated fats was associated with lower sperm counts. Conversely, eating omega-3 polyunsaturated fats (good fats) was associated with better-quality sperm counts.

Infertility is a problem men and women share equally. Managing your weight is something that you can control, and may end up being the difference when trying to bring life into this world. If you are considering starting or extending your family and need to lose weight, talk to your medical provider about your options.