TORONTO - It was a casual comment from a work colleague that launched a CTV's W5 investigation into home DNA test kits people do for fun, like the ones from Ancestry.com and 23andMe.

A producer was curious about her heritage, as she's the child of a Canadian mother and Moroccan father. She wanted to learn more about her genetic makeup.

The test was simple enough: deposit saliva into a plastic vial and send it off to Ancestry.com. A month later, it came back with a precise breakdown. She was ecstatic.

But W5 discovered that DNA home test kits come with rewards and risks.

What my colleague didn鈥檛 know was that her information, her DNA, the most personal and essential part of us, could very easily be in the hands of third parties.

W5 spoke to York University Professor Julia Creet, who has written two books on how commercial DNA companies operate. Professor Creet says, 鈥淭hey are making money by selling the information to other large companies.鈥

鈥淐onsumers are paying to give away their most valuable information, their most private and valuable information.鈥

But sharing DNA from these home tests has also helped police solve cold cases. W5 spoke to the families of Tanya Van Cuylenborg and Jay Cook, two Canadians who were found murdered in Washington state in 1987.

Their killer remained a mystery until 2018, when DNA from a second cousin, who had done a home DNA test, led police to William Earl Talbott II. He has since been found guilty, in the first of its kind court case using genetic genealogy. The technology was also central in the arrest of the notorious Golden State killer. That case has yet to go to trial.

DNA from a home test kit can also reveal family secrets; like your father is not your biological father.

A man we are calling Philip discovered a DNA secret that threatens to tear his family apart. He did not want his identity revealed because others in his family don鈥檛 yet know what he uncovered. Along the way, he also found two half-siblings and an explanation for a host of health issues he鈥檚 had to endure over the years.

In this new world, where technologies have taken DNA out of labs and onto social media, sperm and egg donors can no longer be promised anonymity. Case in point: a California university student, who discovered he had 32 half-siblings thanks to his biological dad, a sperm donor.

Toronto Lawyer Sherry Levitan, who specializes in fertility issues, says home DNA tests have fundamentally changed the nature of sperm and egg donation.

Levitan says 鈥淒onors cannot be promised anonymity and I think it would be a fool鈥檚 errand to promise anonymity.鈥

it "is committed to safeguarding our customers鈥 data and privacy and we give customers control over their own data at all times. We do not and will not share customer DNA data with insurers, employers, or third-party marketers."

The company also says it doesn't share customer information with law enforcement "unless compelled to by valid legal process."

to W5, saying "Beyond the private lab we work with to process your sample and deliver your results, your information will not be shared with any other entity unless you provide us with consent to do so.鈥

Watch 鈥淔amily Secrets鈥 on Saturday鈥檚 season premiere of CTV鈥檚 W5 at 7 p.m.

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