I agree with the gay commentator from the Guardian, he was probably already gay and this basically accelerated his coming-out-process. Plus the dude played Rugby! Isn't just that a sport of dudes grabbing each other's junk?

Becoming homosexual after a stroke damaging a particular part of the brain fits with Greg Cochran's theory homosexuality is caused by a pathogen:

Now that we know that human male homosexuality looks like a disease caused by some infectious organism, the next question is how that could happen - how could some virus change sexual interest?

I don't think that anyone can be sure of the exact mechanism at this point. I think we can be fairly confident that it is caused by an infectious organism, from the information we have and general evolutionary considerations, but infectious organisms can cause harm in many different ways. Malaria colonizes and uses up red blood cells, diphtheria and cholera manufacture toxins, HIV slowly knocks out a key subpopulation of the immune system, leaving you defenseless against many other pathogens, while certain papillomavirus strains deregulates cell division and thus cause cervical cancer. And those are just samples: there are many pathogenic mechanisms involved in infectious disease, some not well understood.

What do we know? We have a lot of indications that there has been some change in the brain. After all, that's the most logical location for the cause of a change in behavior. Simon LeVay and others see differences in hypothalamic nuclei (similar to those seen in sheep). There are associated changes - the lisp, increased neuroticism and depression, etc. Somehow the cause is affecting the brain.

Just as important are all the things we don't see. We don't see IQ depression, we don't see epilepsy, we don't see convulsions, and we don't see aphasia. Clearly there is no gross trauma - somehow, the brain has been damaged, but in a very limited and focused way. A key function has been messed up, which gravely impacts reproductive fitness, but homosexual men can still hold down jobs, including very complex jobs. The overwhelming majority of mental functions are perfectly intact, or at most subtly changed. The damaged neural subsystem could be male-specific.

Do we know of diseases in which there are very specific targets - in which certain cell types are damaged or destroyed while neighboring cells are left intact? Sure. In some cases, a pathogen targets a particular cell type and has little effect on anything else. Human parvovirus (also known as fifth disease) hits erythroid precursor cells (the cells that manufacture red cells) and temporarily inhibits red cell production. In type-I diabetes, it seems likely that Coxsackie virus infections ( in people with a genetic predisposition, in which HLA type plays a major role) trigger an autoimmune disease that gradually (over a year or so) destroys the islet cells which produce insulin. Other cells are not much affected.

If you have an idle hour, you may want to see this BBC documentary about Chris. It answers a few questions, and poses some more. For one thing I was incorrect in the write-up about the sequence of events; Chris' accident took place 7 years ago, not one. Although his physical deficits are pretty minor, he apparently has some major memory lapses from the time before the stroke, which makes many of his assertions about what he felt back then suspect. He certainly seems more interested in the gay issue than the memory losses, and he makes no mention of the grave nature of breaking your neck and having to undergo months of hospitalization and physical rehab.

Also interesting is the fact that he has largely drifted away from his mother, who helped him considerably during his recovery. His attitude about people he knew before has changed, even if he remembers them. I would think someone with such memory lapses would be going through life like a ghost, and then it becomes apparent that he is going through life like at least half a ghost, functional but still tentative. I wish BBC could have interviewed the mother. I don't think the doc answers the question of if a stroke can turn you gay, but it does give some insight into a person trying to rebuild their life after so dramatic an injury.

One scene in particular strikes me as odd. He takes a questionnaire at a ridiculously modernistic college lab to try and determine if he were actually gay before the accident. Nobody comments on the fact that a test that asks, for example, whether in childhood you preferred girlish or boyish toys won't work with a person suffering major memory lapses.