Greets!
I doubt there is a brain chemical that can fix any way of thinking, assuming so is even more foolish than thinking the likes of child molesters and/or rapists have no choice in their actions, due to brain formation.
Despite the formation of one's brain and the chemicals it uses to maintain it's function, conscious thought always has a capability of will. Subconscious or unconscious thought, however, is a completely different beast entirely. Anyone hiding behind the excuse of; 'I had no choice, my ~chemicals~ did it! I have no responsability!' are merely avoiding the concequences of their actions.
Abnormal brain function is something I do not include into this, having a damaged or otherwise different brain that enforces certain logic types is certainly beyond what will can be manifested by the conscious mind, since it stems beyond what can be seen currently.
Does this mean that anyone who is not a paedophile, ever come to understand what it is to have such thoughts? Maybe the first thing that should be considered before an answer is given, is what are your own preferences. Do they match up with what can be considered paedophile? If not, then what do you see a paedophile to be? If you see a paedophile to be a criminal, then what would you seek done to them?
Of course, if you seek anything to be done to a paedophile, anything from 'fixing' them to cutting their bits off for a painful end fitting their 'sickness' then I have some news for you, my friends. By seeking paedophiles, you are criminalising a way of thinking before any crime might happen, as well as laying judgement before a person before they are lawfully and fairly processed by a court, should a crime be committed.
Lets not forget as well that paedophilia is not the same as child molestation or rape, one is a way of thinking and perference that could lead to a crime, where as the other is the crime itself. Someone could have preferences for children, yet never indulge, staying wonderfully covert for their entire lifetime. How does it feel knowing that your neighbour could be a paedophile that hides due to social stigma and fear of the law?
But then, everything I have written here does not mean that I support paedophilia, or would seek to decriminalise child molestation and rape, because I very much do support the laws in the west concerning the protection of children from such things. Children to me are horrible little snot-bags that need time and lots n' lots of money to grow, that may eventually become lovely greater london yobbos, bent on trashing the place someday. As such, children in my opinion should be given the space to become adults, not subjected to something they are simply not ready for.
As such, I can understand what happens to someone who indulges in what is currently a crime, for they face more than the hammer of the law. Indeed, they face a social blackout from their community that will forever label them as 'paedophile scum'
Calling someone else a paedophile when they havn't proven such is ultimately, a really, really dangerous proposition, because there is always someone out there that will ignore the law and exact their own indulging on the paedophile. I mean, having such preferences no longer makes you human, right? So who is going to care.
Apologies but becoming something worse than a paedophile, in reaction to a paedophile, is a thing that would scare me far more, even if it could be considered 'rightious'