For Fruit Flies, Gene Shift Tilts Sex Orientation - New York Times: "In a series of experiments, the researchers found that females given the male variant of the gene acted exactly like males in courtship, madly pursuing other females. Males that were artificially given the female version of the gene became more passive and turned their sexual attention to other males.
'We have shown that a single gene in the fruit fly is sufficient to determine all aspects of the flies' sexual orientation and behavior,' said the paper's lead author, Dr. Barry Dickson, senior scientist at the Institute of Molecular Biotechnology at the Austrian Academy of Sciences in Vienna. 'It's very surprising.
'What it tells us is that instinctive behaviors can be specified by genetic programs, just like the morphologic development of an organ or a nose.'"
I guess the gender of fruit flies is not socially constructed. This is bad news for university professors in the fruit fly community.