Ronsonic's post got me thinking, and I can only recall one time in which I smashed my junk off of the top tube. It was due to a loose quick release on my rear wheel. I stood up to sprint after hastily repairing a flat ..... and WHACK!
Luckily, the forces involved in crashing just seem to make it highly unlikely that the top tube will be headed to the same place as your soft and danglies.
..... now the stem on the other hand .....