ENCINO, Calif-On a recent day in this Los Angeles suburb, Maya Jagdeesh, 35, was being wheeled out of a room at the Fertility Institutes after undergoing an $18,000 procedure to ensure she gets a boy.

Jagdeesh (not her real name) had flown in from Vancouver, B.C., with her husband to Dr. Jeffrey Steinberg's clinic after seeing his online ad that characterizes his pre-implantation genetic diagnosis (PGD) service as "the world's largest and most successful 100 percent sex-selection program."

Jagdeesh said that in her Indian community, most people would assume that her husband or in-laws had forced her to have the procedure. But she insisted she had sought out the clinic herself.

"I know in our culture it's good to have a boy," she said. With two "lovely daughters" ages 12 and 8, she felt having a son would "complete" her family.

"That's the word I hear … from 98 percent of my patients," Steinberg said. "They want to 'complete' their family."

PGD is a combination of in vitro fertilization and genetic screening developed in the early 1990s to identify embryos...