Using mail-order kits to determine the sex of a fetus early in pregnancy for the purpose of selective abortion is unethical, a Canadian medical group said Thursday.

The "pink or blue" blood tests, which can be ordered online for a few hundred dollars, claim to analyze fetal DNA for the presence of the male Y chromosome, allowing the gender to be determined as early as five weeks into pregnancy with an accuracy of at least 95 per cent.

At the start of the Society of Obstetricians and Gynaecologists of Canada annual meeting in Ottawa, the group warned against using the early results to choose a baby's sex through selective abortion.

The group's official policy also condemns as discriminatory the use of medical techniques for sex selection.

"The SOGC remains firmly against the practice of sex selection through selective abortion," Dr. Don Davis, the group's president, said in a release.

"These new technologies are finding their way to Canadian women and are opening the door to a number of ethical questions."

Ultrasounds at 18 to 20 weeks may reveal the gender of a fetus.

Earlier results are available by analyzing amniotic fluid taken in amniocentesis tests at 15 weeks, or in chorionic villus sampling (CVS), which takes cells from the placenta at 10 to 12 weeks of pregnancy.

Amniocentesis carries a risk of about 0.5 per cent of losing the pregnancy; the risk is slightly higher in CVS, according to the group's web site. 

In May, DNA Worldwide, a British company, said it has been sending a couple of test kits a week to Canada. Davis said it's not known how many Canadians are using the test kits or for what reason.

The medical reasons for determining gender, such as a family history of a gender-related chromosomal abnormality, are rare. But using the technology merely to decide on the future of pregnancy based on gender, "we don't think that's a healthy approach," Davis said.

With files from the Canadian Press