Thanks to Rich and also to those who contacted me via inbox rather than here on this discussion board. I have obtained some valuable leads, and Ken was extremely helpful.
In the hope that my efforts might be of future use to someone, I will summarize my findings here.
Ken pointed me to Richard Gartner's book, Betrayed as Boys (Chapter 4) which states:
"The preponderance of sexually abused men are actually more
empathic and less constrained about gender role and emotion
than nonabused men, and so are not likely to become abusers
themselves (Lisak et al., 1996; see also Briggs and
Hawkins, 1996). Apparently, boys who have been able in some
measure to symbolize their victimhood have a comparatively
enhanced potential for compassion and flexibility. Thus,
contrary to popular opinion, most do not become
victimizers."
He also directed me to an inconclusive GOA report at
http://www.gao.gov/archive/1996/gg96178.pdf which reported:
1. There was no consensus among the 23 retrospective and 2
prospective studies reviewed that childhood sexual abuse
led directly to the victim becoming an adult sexual abuser.
2. The retrospective studies, which sought to determine
whether a sample of known sex offenders had been sexually
abused as children, differed considerably in the types of
offenders studied, use of control or comparison groups, and
definition and reporting of childhood sexual abuse.
3. Although some of the retrospective studies concluded that
childhood sexual abuse may increase the risk that victims
will commit sexual abuse later, most of the studies noted
that the majority of sex offenders had not been sexually
abused as children.
4. The prospective studies, which tracked sexually abused
children into adulthood to determine how many became sex
offenders, studied sample populations that may not be
representative of the entire population of childhood sexual
abuse victims.
5. The prospective studies found that victims of childhood
sexual abuse were not more likely than non-victims to be
arrested for sex offenses.
Thanks Ken (and colleagues). My research continues...