The Chinese want boys, and the Canadians want girls. If they have enough money, they come to the United States to choose the sex of their babies.
Well-off foreign couples are getting around laws banning sex selection in their home countries by coming to American soil - where it's legal - for medical procedures that can give them the boy, or girl, they want.
"Some people spend $50,000 to $70,000 for a BMW car and think nothing of it, but this is a life that's going to be with us forever," said Robert, an Australian who asked that his last name not be used to protect the family's privacy.
He and his wife, Joanna, have two boys. Now they want a girl. Australia only allows gender selection of embryos to avoid an inherited disease.
The United States' lack of regulation means a growing global market for a few fertility clinics. These businesses advertise in airline magazines or post Web sites aimed at luring clients worldwide.
Opponents say this amounts to medical tourism for designer babies and should awaken lawmakers.
But one doctor who offers embryo selection for about $20,000 says he is serving the marketplace and helping nature, not playing God. People will be less alarmed as sex selection becomes more routine, said Dr. Jeffrey Steinberg of the Fertility Institutes of Los Angeles and Las Vegas.
"It's new. It's scary. We understand that," Steinberg said. His Web site features an image of a Chinese flag alongside information about sex selection. "Near 100 percent (99.99 percent) effective gender selection methods to help balance families," the site says.
"We basically want them to know it's available," Steinberg said of the international push. The Web page on sex selection generates 140,000 hits a month from China, he said, and the only country outpacing China's interest is Canada.
In a recent week, his clinics performed the procedure on eight women from abroad and consulted with 12 new foreign patients from China, Germany, Canada, the Czech Republic, Guam, Mexico and New Zealand, he said.
The procedure determines the gender of a batch of fertilized eggs and implants only embryos of the wanted sex. This process - called preimplantation genetic diagnosis, or PGD - is more widely used to screen for genetic diseases.
"The Chinese like boys. Canadians like girls. Every country is different," he said, adding that the boy-girl preference balances out at 50-50 when all his clients are added together.
Foes call it "consumer eugenics" and say it opens the door to a future where parents will choose their babies' hair color, eye color and potential to grow tall enough to play basketball. U.S. doctors are catering to the same gender bias that has led to female infanticide in China and India, opponents said.
While many countries prohibit sex selection techniques without a medical purpose, the United States has no such ban.
"We are one of those few countries in the world where sex selection using PGD isn't regulated," said Susannah Baruch, director of the Reproductive Genetics and Public Policy Center at Johns Hopkins University. "It's certainly a magnet for couples for whom this is important."