Two families are taking a prominent Ottawa fertility doctor to court over accusations the doctor used the wrong sperm when he gave them fertility treatments.

The families are now suing Dr. Norman Barwin and his Broadview Fertility Clinic in Ottawa's west end. The lawsuits allege Barwin used a different donor's sperm when inseminating two women, and failed to notify them. Now, the families are demanding to know who fathered their children.

In court documents, Trudy Moore and her husband Matthew Guest claim a blood test confirmed Guest is not the father of their child.

Now, they're asking the doctor to be tested to see if he used his own sperm in the fertility treatment.

Another patient, Jacqueline Slinn alleges she was also a victim, claiming Barwin didn't impregnate her with sperm from her chosen donor. She too wants Barwin tested.

Barwin, a native of South Africa, is a world-leading fertility doctor credited with helping thousands of families realize their dreams to have children. He is also a member of the Order of Canada.

However, Barwin's credibility has been tested in the past when it was revealed he cheated in two marathons.

Still, colleagues can't believe Barwin is being sued.

Dr. Art Leader of the Ottawa Fertility Centre says a mix-up like this is a physician's worst nightmare. He adds he can't imagine Barwin ever mixing up sperm donors intentionally.

With a report from CTV Ottawa's Catherine Lathem