I don't know the answer to that
And it may be that nobody really does.
It certainly seems plausible that the patterns that lead to abuse are set as a kid and then acted out as an adult. And certainly plenty of examples exist of people who did that. However it is also true that it is common for "normal" people in our society to oversexualize youth. This may have biological roots, certainly there is evidence that something has been selecting powerfully for neoteny in humans. Inthane mentioned the speculation at [link|http://www.davidbrin.com/neotenyarticle1.html|http://www.davidbrin...tenyarticle1.html], and that fits here.
Further complicating any attempt to gather reliable statistics is false memory syndrome. Many people honestly believe themselves to have been abused that weren't. This does not minimize the fact that many believe themselves to have been abused that really were - abuse is depressingly common - but it does make statistics gathering harder. Particularly since the nature of how it arises makes people with false memory syndrome more likely to volunteer themselves than people who really were abused.
However I know that some studies were done in the late 80's on abuse cases which were currently going on. (I was interested in this topic at that point since I was dating someone who had been through abuse.) My recollection says that most abusers were not related to the children that they abused. You were, for instance, far more likely to be abused by a stepfather than your real father. In the remaining cases where close relatives abused you, evidence suggested strongly that the abusing relatives were ones who had not participated significantly in your early child care. (This description certainly fit the case of interest to me at the time.) At least one study suggested that making serial abusers participate in early child care for further children lessened the odds that they would abuse.
I don't know whether this evidence has stood the test of time. (I haven't kept track of research on the field since it no longer relates to my life...) However my thought at the time is that there seems to be a family/available dating material dichotomy in people. And participating in early childcare seems to trigger the "family" side of that. (Another line of evidence towards the basic idea - anecdotal reports say that unrelated children raised as one family in a kibutz do not wind up dating each other, even though the adults involved would have no objection.)
All of which goes to say that, with no specific evidence, I lean towards the belief that becoming an abuser depends on a variety of factors of which growing up in an abusive family is only one, and possibly is not even the most important.
Cheers,
Ben
I have come to believe that idealism without discipline is a quick road to disaster, while discipline without idealism is pointless. -- Aaron Ward (my brother)