My two daughters grew up around motorcycles. Once they were four or five if they wanted a ride I'd give them one (totally geared up) but always went out of my way to make it seem no big deal either way. I took MSF dirtbike training with the youngest and her boyfriend. The boyfriend dug it but she wasn't all that excited after the class.
Deep down inside I felt like one of my successes as a parent was that neither kid was all that interested in bikes.
When the youngest moved to Oregon the first thing she did was sign up for the Oregon rider training program. She was saving for a Ninja 250 when she decided to move to New Zealand where she now rides a friends scooter and is saving for her own.
I have always been horrified at the very idea that I would crash and a loved one would be injured. I hate two up with any of them. I don't care who's fault it was I don't believe I'd ever get over it. Everybody in the family enjoys some sort of high risk sport but we all do it on our own.
Everybody has to make their own decisions on this one.