Pesticides have yet another downside for humans--they negatively affect fertility. This is true for both men and women.
While there haven't been studies where researchers intentionally exposed one group of people to pesticides and compared to a control group, there is evidence about pesticide exposure in humans. Migrant farm workers who were exposed to pesticides were guinea pigs, in a way.
Researchers interviewed women who either worked on farms or lived within a short distance from farms where pesticides were used, and the women took significantly longer to get pregnant than women who were not exposed.
The more disturbing problem is what these pesticides do to the fertility of our children. Some compounds used to make pesticides, specifically vincozolin and methoxychlor, permanently affect the chromosomes of the next generation. Vincozolin is anti-androgenic (testosterone is an androgen) and methoxychlor is estrogenic, which means that the effects are worse on boys born to women exposed to these chemicals.
While there aren't formal human studies, in animal studies, male rats born to exposed females had lower sperm counts and abnormal sperm production. And these genetic changes persisted into even later generations.
I was taught in college biology that pesticides had no effect on humans because the target of these chemicals is specific to insects. It's true that pesticides don't kill humans, but that doesn't mean that they can't cause changes in us, like genetic changes. Just as soy is estogenic, some pesticides also have estrogenic effects, and that can be damaging to humans.
To be fair, a lot of these things weren't known when most pesticides were developed. But since we know now, it's time to ban some of them.
The United States has banned some pesticides, but not every country has the same bans, and some of the produce imported from other countries contains the very pesticides banned here. The US is not better than other countries in regards to the use of pesticides--the US allows or has approved some for use that are banned in Europe.
If you're trying to conceive, the best thing to do is eat organic produce. Look for the organic labels, especially on imported grapes. And check out the Environmental Working Group's website for a list of fruits and vegetables that have the highest pesticides concentrations.