A former fertility doctor in Canada has been accused of using his own sperm to impregnate at least two patients.

Dr Norman Barwin is alleged to have carried out the inseminations without the women's knowledge or consent, according to a statement of claim filed in an Ontario court on Tuesday.

The civil lawsuit is being brought by Daniel and Davina Dixon after discovering their 26-year-old daughter Rebecca was not Mr Dixon's biological daughter.

The Dixons, who are seeking punitive and other damages against the doctor, contacted Dr Barwin in 1989 to help them get pregnant.

Their daughter Rebecca was born the following year after what they thought was successful treatment.

"When I was younger, I was often asked if I was adopted. And we laughed about those situations," Ms Dixon told CBC News.

"I don't physically look a lot like my parents, but I look a little bit like my mother's mom ... I was never really concerned that there was any problem."

The family decided to get a test done in February this year after learning that it is unusual for two individuals with blue eyes to give birth to a child with brown eyes.

A blood test and DNA test confirmed Mr Dixon was definitely not Ms Dixon's father.