Canada’s doctors are considering barring obese women from fertility treatments after research shows some of those women who undergo in-vitro fertilization treatments have higher risks of complications.

The question will be discussed at a conference in Toronto this week.

Critics are calling the proposal discriminatory. One doctor told the Globe and Mail that smoking also presents risks, including pre-eclampsia and small babies, but fertility clinics still treat smokers.

Age is another risk factor, and the older a woman is, the more difficult it is for her to conceive. Waiting for a patient to lose weight before starting IVF treatments could decrease one risk factor while increasing another.

A woman is considered obese is she has a Body Mass Index of 30 or more. At least one clinic in Ottawa is already refusing to treat women with a BMI of 35 or more.

With files from The Canadian Press