The answer to that question has long been a qualified "maybe." Why maybe? It makes sense that diet and other lifestyle choices affect fertility, for better or for worse. But there hasn't been any good science linking the two. Sadly, we know much more about how nutrition affects fertility in cows, pigs, chickens, and other commercially important animals than about how it affects reproduction in humans.

That's changing. The first comprehensive look at connections between diet and fertility offers good news for couples who are having trouble getting pregnant. A series of studies from the landmark Nurses' Health Study has identified a number of dietary and lifestyle factors that influence fertility, largely by their effects on ovulation. These include:

Avoiding trans fats, the artery-clogging fats found in many commercial baked goods and fried fast foods, and using more unsaturated vegetable oils

Switching from highly refined grains to whole grains and other good sources of slow carbs

Adopting a more "flexitarian" approach to main courses, with more beans, fish, vegetables, and nuts and less red meat

Taking a daily supplement with folic acid and iron

Getting into the fertility zone for weight and physical activity

And, for those who enjoy milk and dairy products, having 1 or 2 servings a day of whole milk, full-fat cheese, or ice cream.

These strategies appear to improve ovulation and help protect against ovulatory infertility. Following five or more of the recommendations in The Fertility Diet lowers the risk of ovulatory infertility by 80%. Equally important, the diet sets the stage for a healthy pregnancy and forms the foundation of a healthy eating strategy during pregnancy, motherhood, and beyond.

At least for now, these recommendations are aimed at preventing and reversing ovulatory infertility, which accounts for one quarter or more of all cases of infertility. They certainly won't work for infertility due to physical impediments like blocked fallopian tubes.

The plan described in The Fertility Diet doesn't guarantee a pregnancy any more than do in vitro fertilization or other forms of assisted reproduction. But it's virtually free, available to everyone, has no harmful side effects, and is an altogether healthy eating strategy. That's a winning combination no matter how you look at it.