A healthy baby with genetic information from two mothers and one father was recently born in Mexico, conceived via a controversial method that aims to help prevent genetic disorders from being passed from parent to child. Researchers published details about the technique, called spindle nuclear transfer, in the journal Fertility and Sterility and regard the procedure as an “exciting” new advancement in reproductive technology, CNN reports.

Spindle nuclear transfer involves adding a number of genes from a donor woman into the egg of the mother before using sperm from the father to fertilize the egg and create an embryo. The technique, which is currently unavailable in the United States, was used to prevent Leigh syndrome, a severe neurological condition that the baby’s mother was carrying in her genes.

Since the U.S. Food and Drug Administration hasn’t approved the procedure in this country, a team of doctors from the New Hope Fertility Center in New York City flew to Mexico with the parents to perform the three-parent fertilization. Many in the U.S. medical community questioned the parents leaving the country to undergo the procedure. They suggest that sidestepping the rules could undermine scientific developments in genetic modification, which requires tight controls to minimize risk to patients.

“It’s unfortunate to have people decide they’re just going to quite willingly engage in this kind of reproductive tourism—to go outside of a system that is in place to create the safest, most scientifically reproducible way forward,” said Lori P. Knowles, adjunct assistant professor at the University of Alberta School of Public Health. “That’s the precedent then, that if you think you can do it, then let’s just hop the border and see what happens, hope for the best.”

Doctors around the world are also concerned about the health of the 6-month-old boy born using this three-parent procedure. Physicians are concerned that although the baby seems to be healthy right now, there’s still a risk that eventually he might develop a disease.

Did you know that parents-to-be are also starting to use reproductive services to make their babies more attractive? Click here to learn more.