Have you heard of Katie Ledecky? If you haven't, Katie Ledecky is the best female 1,500 meter swimmer of all-time. And Katie Ledecky won't be swimming the 1,500 meter in the 2016 Rio Olympics because only men are allowed to compete at that distance. The furthest distance Ledecky is allowed to swim is 800m. Same thing with cycling; the women's track is 62 miles longer, and the issue is not about safety, it's about suppression.

Source: http://www.wsj.com/articles/at-the-rio-olympics-women-athletes-bump-against-a-gold-ceiling-1470425132