I know of four propositions that might explain a genetic origin of paedophilia.

-Cirrus, kind of(1): Another gene may incidentally predispose one to the development of paedophilia. Even if paedophilia itself serves no procreative purpose this might be true: an aspect of our current social environment might 'trigger' sexual attraction to children, or any possible evolutionary disservice of paedophilia might not be enough to offset the "carrier" gene's benefit.

-Donald Symonds?(2): "An ancestral male who married a nubile (or somewhat younger) female [and carry the relationship into puberty] would have had maximum opportunity to sire her offspring during her most fecund years and, more important, would not have had to invest in children that had been sired by other men or to incur the various costs involved in ongoing conflict with the mother over how she allocates her parental effort among his and other men's children. Also, a nubile woman, compared to a woman even a few years older, would not have been investing her time and energy in other men's children, would have had more living relatives to invest in her and her children, and would have been more likely to survive until a newly conceived child was old enough to survive on its own."

-jd420(3): The children who paedophiles are driven to enhance the well-being of   /cgi/deref.cgi?url=http://violence.de/   tend to be related. (kin selection)

-Richard Gardner(4): Girls who have sexual contact with an adult in their childhood are significantly more likely to engage in risky, procreative sexual behavior. Browning and Laumann (1997) found that "...women who experience adult-child sexual contact are, clearly, more sexually active in both adolescence and adulthood. They have sex at earlier ages during their teenage years and are more likely to bear children before they turn 19."(5)

Only the third (which I prefer) and first could explain the hypothetical evolution of boylove or exclusive paedophilia.

AFAIK, the only evidence for this hypothetical origin can be drawn from Gaffney et al. (1984)   /cgi/deref.cgi?url=http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=6470698&dopt=Abstract  , the animal kingdom   /cgi/deref.cgi?url=http://kalapa.nfshost.com/viewtopic.php?id=24  , and the ubiquity of paedophilia in human history.

Are there other explanations or evidence that I could be pointed to?

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1. "I don't believe that there is a pedophilia gene, so the job here is not explaining why this gene has continued to replicate. Rather, it is a job of explaining why there is a process whereby a certain genetic combination interacting with an environment produces individuals who respond sexually to features which are unique to children." -Benson's Story   /sheepy/perspective/minstrel/Benson2.html  

2. "Sexual Nature, Sexual Culture" (Ed. by Paul R. Abramson and Steven D. Pinkerton, University of Chicago Press, 1995, Chapter Five: "Beauty is in the Adaptations of the Beholder: The Evolutionary Psychology of Human Female Sexual Attractiveness") Quoted by N.S. Aristoff   /cgi/deref.cgi?url=http://web.archive.org/web/20010126141800/http://www.lelnet.com/asg/dirs/1998-03-1/10347  

3. "...not only are the children whose well-being one is driven to enhance statistically mildly related to you in a polyamorous tribal-ish society..." -Just a hypothetical... ;)   /messages/234186.htm  

4. "The younger the survival machine at the time sexual urges appear, the longer will be the span of procreative capacity, and the greater the likelihood the individual will create more survival machines in the next generation." Gardner, Richard A., True and False Accusations of Child Sex Abuse (1992), pp.24-25. Quoted here   /cgi/deref.cgi?url=http://www.thelizlibrary.org/liz/pedoph.htm  

5. Sexual Contact between Children and Adults: A Life-Course Perspective, American Sociological Review, Vol. 62, No. 4 (Aug., 1997), pp. 540-560. A pdf of this is available on JSTOR or from me.