This is one of those difficult to answer questions. One that gets asked by social workers on courses that I run. The figures are heavily skewed towards men as sexual abusers - and I believe this to be true, with one big caveat and it's to do with our own biases. Society doesn't think women can be sexual abusers because it 'goes against their nature'. I think this is short-sighted in the extreme, as it is often abuse or psychological disturbance that generates the predisposition to abuse children.

There's a model called the 'Four preconditions' model by Finkelhor which sets out the following stages. (1) an offender with a predisposition to sexually abuse a child; (2) the ability overcome any internal inhibitions against acting on that predisposition; (3) the ability to overcome external barriers, such as lack of access to the child or supervision of the child by others; and (4) the ability to overcome any resistance or reluctance on the part of the child.

I would say the first condition is more common in men than women..... but from that point on, it becomes far easier for women to abuse children. There may be fewer women abusers, but those that do go on to abuse will do so with relative ease and be difficult to uncover. Women generally have more accesss to children, often unsupervised, and so I think the figures are likely higher than we would imagine. We aren't finding it because a) it isn't there or b) we aren't looking. I'm prepared to accept that the former is true, but only if the latter is properly done - and I don't think it is.