Here's what I know.
Parabens are preservatives used in lots of personal care products and cosmetics. They are thought to mimic estrogens and studies have found them in breast cancers (although there's no way to prove if they are causative or not). Just like other things that act like estrogens (PAH, dioxins, many pesticides...) they may IN THEORY interfere with the reproductive cycle in both men and women and may also interfere with the normal sexual development of the male fetus.
If you are concerned, just read labels...its getting easier to avoid them (especially products from Europe)