One-fourth of the experiences could be described as exploitative either because force was used or because there was a large age disparity between the partners.
If you look hard enough, Mary-Kate will flash you back to that moment in It Takes Two where her cover is about to be blown, so she puts a chef's hat over her face to hide herself.
In the last five minutes, as she left town, the girl told the lead policeman's doctor wife in confidence that the actual father was her brother.
Sometimes there is no reason at all as all people are different, including children and other times a child may have seen something that started them down a different path.