A new at-home test that can determine the gender of a fetus at 10 weeks with 80 per cent accuracy might sound exciting to some but it worries others.

The Boy or Girl Gender Prediction Test "bridges the curiosity gap between conception and sonogram," claims its manufacturer, IntelliGender. More than 50,000 tests have sold online off the company's website. Now, U.S. drugstore chains CVS and Walgreens have begun selling the test over the counter for US$34.95.

The kit tests a small amount of the mother's urine that is added to a cup and mixed with the kit's "proprietary mix of chemicals" that reacts to certain gender-specific hormones in the urine.

If the test strip turns orange after 10 minutes, it's a girl; if it's green, it's a boy. If multiples are expected, orange will indicate all babies are females, while green means that at least one of the multiples is male.

The manufacturer says the product is about 80 per cent accurate when taken at home, with laboratory results coming in at more than 90 per cent.

IntelliGender insists they can't promise that the test is always right, which is why they post this warning on their website: "IntelliGender does not recommend test users to make any financial, emotional or family planning decisions based on the test results. This includes painting a nursery!"

Medical ethicist Margaret Somerville of McGill University says the test sounds like a nice idea for some, but she worries it could be used for the wrong reasons by others.

"You could use it for a benign purpose - you know, you're curious to know the sex of your baby as soon as possible - or it could be used for sex selection, in that if you identify that the child is the 'wrong' sex - usually a girl - then you might have an abortion. And so it brings us into the whole thorny issue of abortion," she explained to Canada AM from Montreal Wednesday.

"I think there would be quite a lot of people who would use it because they're excited to be pregnant and they're going to have the baby no matter what and they just would like to know its sex. But I also think there are going to be people who do it as early as possible because they don't want a baby of a certain sex."

Somerville worries what would happen if people in countries that have huge problems with sex selection, such as India and China, had access to this test. In such countries, boy babies are greatly preferred for both cultural and economic reasons, and the aborting of girl babies has become common.

"It's not just the loss of those babies, and it's not just the trauma to the women who are forced to have an abortion if it's found they are carrying a girl," says Somerville. "It's also the societal impact, in the lack of women to marry. Later on, all these men have the problem that they can't find a wife. That causes all sorts of problems."

Somerville says some may argue that couples have the right to do what they want in their family planning decisions, but she's not sure she agrees.

"People who are very strongly pro-choice sometimes say that if it's a matter of choice, for no matter what the reason, a woman has the right to choose that she doesn't want this baby. I think that's extraordinarily dangerous. I think it's also an example that the decision of an individual person doesn't just relate to them, it affects society."