GENETIC factors, as well as circulating hormones, are responsible for differences between male and female brains, according to a study of a rare mutant zebra finch.
Cells on the left side of the bird’s brain are genetically female, while cells on the right are genetically male. A team led by Art Arnold at the University of California, Los Angeles, found that the neural song circuits on both sides were more masculine than those found in female zebra finches, as might be expected if hormones are involved. But they also found that the song circuit on the right side of the mutant finch’s brain appeared more masculine…
