University of Utah biologists have genetically manipulated nematode worms so that the animals were attracted to other worms of the same sex – creating in essence “lesbian” worms.
The results bolster theories that sexual orientation is wired into our brains.
“They look like girls, but act and think like boys,” says Jamie White, a postdoctoral researcher and lead author of the new study. “The [same-sex attraction] behavior is part of the nervous system.”
The study will be published in the Current Biology journal in November.
“We cannot say what this means for human sexual orientation, but it raises the possibility that sexual preference is wired in the brain,” says laboratory leader and biology Professor Erik Jorgensen.
He adds that, “Humans are subject to evolutionary forces just like worms. It seems possible that if sexual orientation is genetically wired in worms, it would be in people too.”
Nematodes worms are millimeter-long worms that live in soil and eat bacteria. Because the same genes are found in many animals, nematodes, mice, zebrafish and fruit flies often are used as “models” for humans in research.
“People debate whether the brain is influenced by sexual hormones from the gonads or whether the behavior is derived from the brain alone,” Jorgensen says. “In this case, it’s clear the brain is sexualized.”
The belief that humans have a choice in deciding their sexuality is at the core of many conservative and religious attitudes towards gays and lesbians. Scientific evidence, however, is increasingly pointing to the conclusion that sexuality is biologically or genetically based and is not by choice or lifestyle.