In the first study of its kind, Harvard University has taken an in depth look at the effect of pesticide residues on the volume and quality of sperm.

Although there is a lot known about the effects of lifestyle and environmental factors on men’s fertility – like alcohol and tobacco, along with wearing tight underwear which can overheat the testicles – amazingly no research had been done to-date on what effect chemical pesticides could have.

It being the first study, it has left a lot of unanswered questions and the researchers acknowledge that a lot more work needs to be done, but the results were such that they are convinced that there is a strong connection.

The researchers used U.S. Department of Agriculture data to classify the levels of pesticide residue in 35 fruits and vegetables between 2006 and 2012. 155 men were asked how much of each they ate (they averaged .9 daily servings of high-pesticide produce and 2.3 servings of low- to moderate-pesticide fruits and vegetables), then checked their semen samples for a variety of problems.

Men who consumed the largest amounts of high-residue fruits and vegetables had 49 percent lower sperm counts, 32 percent fewer normal-appearing sperm and a 29 percent lower ejaculate volume than men who ate the smallest amounts of those fruits and vegetables.

Everyone acknowledges that eating plenty of fruit and vegetables is an essential part of a healthy diet, but in view of this research, Fertile Matters would advise men to choose organically produced fruit or vegetables or to reduce their consumption of varieties that tend to have a lot of pesticides used in their production.

The ones to avoid or cut down on are:

Apples, celery, cherry tomatoes, cucumbers, grapes, nectarines, peaches, potatoes, sugar snap peas, spinach, strawberries, peppers, chillies and kale.

Instead, you can try to incorporate fruits and vegetables that generally have small amounts of pesticide used in their production:

Asparagus, avocado, cabbage, Cantaloupe melon, cauliflower, aubergine (eggplant) grapefruit, kiwi, mangoes, onions, papayas, pineapples, sweet corn, frozen peas and sweet potatoes.

You can read the full study here.