How Life Letters is changing the face of genetics testing for parents-to-be.

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When two people decide to start a family, there’s no way of knowing precisely which health outcomes might be passed on from parent to child. In some cases, adults can carry recessive genetic disorders — sometimes quite severe ones — without even being aware of it.

But that’s beginning to change.

Warren Lee and Dr Sam Prince have founded a genetics testing company to help Australians understand their bodies and make informed choices about the health of their future families. Life Letters, based in Sydney, currently offers two tests that can be ordered online and taken at home.

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The first is Tiny Letters, a saliva test that helps to determine whether future parents are at risk of passing on any of nearly 150 recessive genetic disorders, including cystic fibrosis and Tay-Sachs disease.

"The weird thing about all these diseases is that you inherit two copies of every gene, one from your mum and one from your dad. If you get one good copy, and one bad copy, the good one takes over. But if you have a child and you and your partner both have a bad one, then there’s a one in four chance that the child will inherit both bad genes and have the disorder," Lee, Life Letters' CEO, explains to The Glow.

The test, which currently costs $900 and requires no doctors referral, involves prospective parents sending a saliva sample to be DNA tested in a US laboratory. The results generally take between four and six weeks to come back, and are delivered by a genetic counselor who can explain what they mean and what the options are moving forward.

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In situations where a woman is already pregnant and there isn't much time to work with, Lee recommends both partners take the test concurrently. However, it's preferable for the test to be completed prior to pregnancy; if there's no rush and one partner has taken the test and is not a carrier, there's no need for the other to do the test.

Ultimately, the test aims to give parents the opportunity to prepare for what's ahead or make choices about reproduction. (Post continues after gallery.)

"It's perfectly normal for people to say, 'Okay, this test tells us that there is a one in four chance that our kid is going to have cystic fibrosis, we are going to learn everything we can and talk to the Cystic Fibrosis Association and then make the decision whether we are going to run that risk or whether we are not going to run it'," Lee says.

Although it's easy to assume people would know if they carried an illness like cystic fibrosis, Lee says this isn't the case; in fact, 80 per cent of people who have kids with cystic fibrosis have no known family history of it.

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"The other thing that's interesting about the 149 conditions is that individually they’re quite rare, but collectively they’re about twice as common as Down syndrome ... In a world where people will spend $600 on a pram, [testing] just seems like a sensible thing to do," he adds.

The second test offered by Life Letters is called Script Letters, which can detect how individuals metabolise prescription drugs. This can determine the speed and efficacy with which a drug works — and give an indication of whether certain drugs are right for the patient using them.

"If you burn through them faster [than average] you might get a toxic affect, because something that might be slowly absorbed over 24 hours may get rapidly absorbed over six, which is not what you want. If you were slowly metabolising it, you may be getting no affect at all," Lee explains.

The issue of genetic testing is a highly controversial one, particularly when it comes to childbirth. Lee says Life Letters has faced "a little bit" of push-back since its inception.

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"One of the first things we did when we started this business is we deliberately decided that we would start with the areas that were less controversial... We don't do sex or eye colour selection. We have stayed away from all of those things," he explains.

"If you and your partners are both carriers [of disorders], you have a one in four chance of your child getting them. If you’re not, it doesn't. It's really straightforward." (Post continues after video.)

Ultimately, however, Lee says the Life Letters team is "constantly" striving to do the right thing, and aims to empower Australians to have a say in their health.

"We have a lot of those debates all the time …  You’ve got to have a good reason not to let people make their own choices."

Have you heard of Life Letters before? What do you think of their work?