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This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.

Some people are worried that the more we learn about genetics, the closer we’ll get to a day when we can choose all sorts of characteristics for our babies: eye color, intelligence—and sex. Well, when it comes to sex, finches are a step ahead of us. Researchers in Australia show that female Gouldian finches can select the sex of their offspring. They published their research in the March 20th edition of the journal Science.

Gouldian finches have either red or black colorations on their heads. They choose their mate based on that head color. So researchers played a trick on the animals. They painted the heads of some red males black. Then they mated those seemingly black-headed birds with both red and black females. When the black females thought they were mating with a black male, they produced equal number of baby girl and boy birds.

But the red finch¹ females who thought they were mating with an incompatible² black-headed male had significantly more baby boys. Researchers say this is probably to reduce investment in what they call ‘inviable females.’ And they had fewer and smaller eggs. Truly a clutch performance.

Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber.