The Neurocritic has compiled a collection of interesting neurological studies where a number of patients seems to have experienced a profound change in their sexual preferences as a result of brain disturbance.

One of the most well-known of these studies is a recent case of a man who was convicted of paedophilia late in life, but was later found to have a brain tumour, and on removal of the tumour his sudden interest in children disappeared. It reappeared again when the tumour once more began to grow.

The case has raised questions about free will and self-determination in light of the fact that such morally reprehensible acts seemed only to occur when a tumour was affecting brain function.

It’s importantly to mention that brain damage rarely causes such tragic events, although sexual difficulties, in general, are not uncommon. Problems can range from difficulties with arousal and enjoyment, to behavioural disturbances and inappropriate behaviour.

In some rare cases, preferences themselves seem to be affected, although it’s never clear whether it’s actually that the person has different desires, or whether they always had them but now are, perhaps, less able to stop themselves acting on them.

It’s easier to think that damage has changed people’s desires when the behaviour markedly unusual, such as this case of a man who was, to put it bluntly, screwing the coin return tray of a public telephone after brain deterioration.

But one thing we know from the forensic literature and cases of healthy people who accidentally die during sexual practices (for example, these two), is that no matter how strange the attraction seems to you, someone is out there expressing it.

Not all of the cases of changes sexuality after brain damage are where people act outside of the norm, of course. In one, admittedly, not brilliantly detailed case, an apparently exclusively homosexual man found he developed heterosexual attraction after a stroke.

Sadly, this area is massively under-researched so we really know relatively little about how different aspects of desire, emotional attachment and sexual behaviour are handled by the brain, but these case studies give us a window into the possibilities.

Link to The Neurocritic on ‘Unusual Changes in Sexuality’.