For most couples, the chances of having twins without fertility treatments are low. Triplets are considered a rarity.

But an Ottawa-area family has defied these odds, producing twins, triplets, and then another set of twins over the course of two generations.

This unlikely family tree began taking shape in 1990 when Laurie and Pat Scissons of Ashton, Ont. found out they were having twin boys--Kenny and Robert. Less than two years later, Laurie gave birth to triplets John, Ryan and Scott.

“They started counting--one, two and three. I was smiling pretty hard and Laurie was in tears,” Pat told CTV Ottawa. “Our family doctor said it was a one in a million chance to have twins and triplets without fertility drugs.”

Fast-forward to six weeks ago and the Scissons continue to defy the odds with the birth of yet another set of twins. Emett and Warren were born to Laurie and Pat’s 24-year-old son Scott--and his girlfriend Erika Timmins.

The addition of these newest multiples to the Scissons clan has left the family’s doctors stumped by what they’re calling a complete coincidence.

“Because (Emett and Warren) are identical, it’s a fluke,” Timmins said. “It doesn’t follow a genetic path, I guess.”

According to Multiple Births Canada, about 6,000 sets of twins are born in Canada each year. The organization estimates that a combined 100 sets of triplets, quadruplets and quintuplets are born each year.

MBC says the likelihood of a Canadian couple having a multiple-birth pregnancy is 3.2 per cent, making the Scissons’ streak of twins and triplets a statistical anomaly.

And the family is in for even more baby excitement this summer. John Scissons and his fiancée Amanda Hemphill are expecting in June.

“I would like a girl…to change it up, but with all the boys in this family, she would be in trouble,” Hemphill said with a laugh.

Her first ultrasound only shows one heartbeat, but everyone in the Scissons family knows the unexpected could still happen.

With a report from CTV Ottawa’s Megan Shaw