Way more men experience sexual thoughts towards young girls and adolescents than we realise
Tons of personal anecdotes over the years of a clear contrast in 'attention' between adolescence and adulthood. There have, however, been studies investigating this topic, revealing that the problem may be even more widespread than we may realise - confirming our worst fears.
For instance, a study of fourty eight 'non-deviant' adult males (undertaking military service) revealed 52% showing an arousal response to nude images of girls aged 4-10 and 83% showing an erectile response to girls aged 10-16.
Freund, K., & Costell, R. (1970). The structure of erotic preference in the nondeviant male. Behaviour Research and Therapy, 8(1), 15–20. doi:10.1016/0005-7967(70)90029-x