From FALLOUT: A Survivor Talks to Incest Offenders (and Others) by moi:

 

I observed that it is not at all unusual for men with both sons and daughters to be convicted of molesting a daughter, while denying any molestation of a son. I suppose sons are more reluctant to report than daughters, feeling that it casts aspersions on their masculinity.  When one man’s family (excepting the admitted victim) visited him in prison,  the father made fun of the length of his son’s hair, and asked him if he wanted a bobby pin. The young man in question had been reported to be depressed and self-mutilating.  Later, after I had queried the father, the son wrote a letter assuring me that his father had never molested him. (p. 68)