https://en.wikipedia.org/wiki/Toxoplasma_gondii
Toxoplasma gondii (IPA: /ˈtɒksoʊˌplæzmə ˈɡɒndi.aɪ/) is an obligate intracellular, parasitic alveolate that causes the disease toxoplasmosis.[3] Found worldwide, T. gondii is capable of infecting virtually all warm-blooded animals,[4] but felids such as domestic cats are the only known definitive hosts in which the parasite can undergo sexual reproduction.[5]
In humans, T. gondii is one of the most common parasites in developed countries;[6][7] serological studies estimate that 30–50% of the global population has been exposed to and may be chronically infected with T. gondii, although infection rates differ significantly from country to country.[8][9] For example, previous estimates have shown the highest prevalence of persons infected to be in France, at 84%.[10] Although mild, flu-like symptoms occasionally occur during the first few weeks following exposure, infection with T. gondii produces no readily observable symptoms in healthy human adults.[8][11][12] This asymptomatic state of infection is referred to as a latent infection and has recently been associated with numerous subtle adverse or pathological behavioral alterations in humans.[8][13] In infants, HIV/AIDS patients, and others with weakened immunity, infection can cause a serious and occasionally fatal illness, toxoplasmosis.[11][12]
T. gondii has been shown to alter the behavior of infected rodents in ways that increase the rodents' chances of being preyed upon by felids.[10][14][15] Support for this "manipulation hypothesis" stems from studies showing T. gondii-infected rats have a decreased aversion to cat urine.[10] Because cats are the only hosts within which T. gondii can sexually reproduce to complete and begin its lifecycle, such behavioral manipulations are thought to be evolutionary adaptations that increase the parasite's reproductive success.[10] The rats would not shy away from areas where cats live and would also be less able to escape should a cat try to prey on them. The primary mechanisms of T. gondii–induced behavioral changes in rodents is now known to occur through epigenetic remodeling in neurons which govern the associated behaviors;[16][17] for example, it modifies epigenetic methylation to cause hypomethylation of arginine vasopressin-related genes in the medial amygdala to greatly decrease predator aversion.[16][17] Widespread histone-lysine acetylation in cortical astrocytes appears to be another epigenetic mechanism employed by T. gondii.[18][19] Differences in aversion to cat urine are observed between non-infected and infected humans and sex differences within these groups were apparent, too.[20]
A number of studies have suggested that subtle behavioral or personality changes may occur in infected humans,[21] and infection with the parasite has recently been associated with a number of neurological disorders, particularly schizophrenia[15] and bipolar disorder.[22] A 2015 study also found cognitive deficits in adults to be associated with joint infection by both T. gondii and Helicobacter pylori in a regression model with controls for race-ethnicity and educational attainment.[23] Although a causal relationship between latent toxoplasmosis with these neurological phenomena has not yet been established,[8][15] preliminary evidence suggests that T. gondii infection can induce some of the same alterations in the human brain as those observed in mice.[24][25]
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If a parasite like Toxoplasma Gondii can cause behavioral changes in humans, cats, and rodents why couldn't there be a similar infection for homesexuality?
However, in the case of homosexuality, I don't know of a single shred of evidence suggesting a microbial or viral agent even correlated with the orientation. And, of course, even correlation would not necessarily be evidence of causation.
Certainly homosexuality is a very complex bunch of stuff. I've just never heard of any evidence of such an etiology as you hypothesize.
imho, the old dopamine reward cycles & related behavior-mod connections are more than sufficient to explain the orientation.
You’d think that if there was a parasite or infectious agent that caused it, it would be found in all homosexuals and would have been discovered by now, especially during the search for the cause of HIV.
There is a lot of things wrong with that theory.
“Toxoplasma Gondii” and rabies, along with other more extreme examples in nature, are reasons why I tell my kids “These zombie shows?? You never know.....”