A modern baby making technology that has the power to screen out diseases even before the mother is pregnant is raising ethical questions about the potential to create so-called "designer babies."

Chris Kirby and Tanya Fawkes-Kirby of Port Moody, B.C., have three daughters: Morgan, 3, and twin girls, Teagan and MacKenzie, who are five-months-old.

After their eldest was born, Kirby's heart condition took a dramatically worse turn.

"Prior to that I was running and going to the gym and then to the point that I couldn't walk 50 yards without having to stop", said Kirby.

Kirby was born with hypertrophic cardiomyopathy, a genetic heart disease that can lead to sudden cardiac arrest at any age. The family feared the worst. Kirby's wife said they made all the preparations her to become a single mom.

Then last June, Kirby underwent a successful heart transplant.

Long before his transplant, they knew they wanted more children but they weren't willing to risk passing on the potentially deadly condition to their kids. The chances were 50/50.

They instead embarked on the expensive strategy of In Vitro Fertilization (IVF) with pre-implantation genetic diagnosis -- or PGD. A cell is removed from the embryo and then tested for the disease. Only the embryos without the genetic defect are then implanted in the mother's uterus. Doctors say it's very effective.

"PGD has been an incredible development that enables us to screen out disease," said Dr. Albert Yuzpe, of the Genesis Fertility Centre.

It worked for Tanya and Chris. After two IVF cycles, Tanya became pregnant with twins, who did not carry the heart disease their father was born with.

Eight days after Chris welcomed a new heart, he welcomed his twin daughters into the world.

"The technology is amazing. I was so excited we had this as an option," he said. Kirby adds the potential is huge. "If we can imagine getting rid of my condition or Huntingdon's Disease."

But some critics fear this type of screening could be used to play God and create "designer babies."

"We need to ask questions about the kinds of conditions we want to screen. Are we in practice actually setting a kind of admission standard so that only some embryos are good enough to implant?" said Anita Ho from the University of British Columbia Centre for Applied Ethics.

The technology was used about 50 times in 2009. Fertility experts dismiss any fears of eugenics.

"We are not in the designer baby business. No one is interested in making babies with blonde hair and blue eyes or whatever," said Dr. Albert Yuzpe.

Yuzpe points to the opportunity to save the health care system millions of dollars and he's urging the province to cover the cost.

"The government will pay for testing once it's in the uterus, but they won't pay for it beforehand. The technology is expensive and that to me is very wrong," Yuzpe said.

PGD costs about $4,000 for the first screening. When you add the IVF costs, Chris and Tanya spent almost $30,000 to make sure their daughters would be born healthy.

For them, the payoff is invaluable.

"I don't have to worry about them running in a park and possibly collapsing from a cardiac arrest…and the potential of them passing it on to their children," said Kirby. "I'm thankful every single day we're not going to have to worry about our children."

With a report from CTV British Columbia's Mi-Jung Lee