Chicago ? The power to create “perfect” designer babies looms over the world of prenatal testing.

But what if doctors started doing the opposite?

Creating made-to-order babies with genetic defects would seem to be an ethical minefield, but to some parents with disabilities – say, deafness or dwarfism – it just means making babies like them.

And a recent survey of U.S. clinics that offer embryo screening suggests it’s already happening.

Three percent, or 4 clinics surveyed, said they have provided the costly, complicated procedure to help families create children with a disability.

Some doctors have denounced the practice, while others question if it’s true. Blogs are abuzz with the news, with armchair critics saying the phenomenon, if real, is taking the concept of designer babies way too far.

“Old fear: designer babies. New fear: deformer babies,” the online magazine Slate wrote, calling it “the deliberate crippling of children.”

But the survey also has led to a debate about the definition of “normal” and inspires a glimpse into deaf and dwarf cultures where many people do not consider themselves disabled.

Cara Reynolds, of Collingswood, N.J., who considered embryo screening but now plans to adopt a dwarf baby, is outraged by the criticism.

“You cannot tell me that I cannot have a child who’s going to look like me,” Reynolds said. “It’s just unbelievably presumptuous and they’re playing God.”

Embryo screening, formally called preimplantation genetic diagnosis, is done with in vitro fertilization, when eggs and sperm are mixed in a lab dish and then implanted into the womb. In PGD, before implantation, a cell from a days-old embryo is removed to allow doctors to examine it for genetic defects.

Cara and Gibson Reynolds, whose newborn died last year from a genetic condition linked to dwarfism, pose Dec. 16 on the porch of their home in Collingswood, N.J. Cara says she is outraged by opposition to using embryo screening to allow dwarf people to have dwarf children. A recent survey of U.S. clinics offering embryo screening suggests it's already happening.

The entire procedure can cost more than $15,000 per try.

The survey asked 415 clinics to participate, 190 responded and 137 said they have provided embryo screening. The most common reason was to detect and discard embryos with abnormalities involving a missing or extra chromosome, which can result in miscarriage or severe and usually fatal birth defects.

The survey is being published in an upcoming print edition of the medical journal Fertility and Sterility. It appeared in the online edition in September. Clinics were asked many questions about PGD, including whether they’d provided it to families “seeking to select an embryo for the presence of a disability.”

While it’s technologically possible, whether any deaf or dwarf babies have been born as a result of PGD is uncertain. The survey didn’t ask. Participating clinics were promised anonymity, and seven major PGD programs contacted by The Associated Press all said they had never been asked to use the procedure for that purpose.

PGD pioneer Dr. Mark Hughes, who runs a Detroit laboratory that does the screening for many fertility programs nationwide, said he hadn’t heard of the technology being used to select an abnormal embryo until the survey.

“It’s total nonsense,” Hughes said. “It couldn’t possibly be 3 percent of the clinics” doing PGD for this purpose “because we work with them all.”

He said he wouldn’t do the procedure if asked.