Long shifts. Unpredictable hours. And physically demanding work. The job of a surgeon isn't easy for anyone — but for women trying to juggle work with family life, it's particularly daunting.

"Out of seven days last week, five of those days I was on call for 24 hours. It's challenging when you have a family," says Carolyn Nessim, a surgical oncologist at the Ottawa Hospital. "But I love my job, and I love what I do, and I feel enormous amounts of gratification from my work."

Viewers got a glimpse into Nessim's passion in Part 4 of Keeping Canada Alive, during which she performed a preventive mastectomy on Tina, a woman who had breast cancer 20 years ago and had tested positive for one of the breast cancer genes, BRCA2.

As a female surgeon, Nessim is in the minority — a sizable gender gap that stands out all the more as increasing numbers of women choose to become doctors.

Between 2010 and 2014, the number of female physicians rose by 24 per cent, while the number of men increased by only 10 per cent, according to the Canadian Institute for Health Information's annual report on physicians in Canada. Most are becoming family physicians — women now make up 44 per cent of family doctors — but many fewer are choosing surgery

According to the report, released this fall, there are 7,240 male surgeons across the country, and 2,494 female surgeons — with nearly half of them in obstetrics and gynecology.

In some subspecialties, the imbalance is stark. Neurosurgery has 288 men and 32 women; cardiac surgery, 315 and 38.

The field of surgery is seen as more physically demanding than other types of medicine, as surgeons need to stand longer and perform repetitive, fine movements.

My job has cost me and my family a great deal. And I just hope they forgive me for the days that I wasn't there. But it's who I am. - Dr. Joan Murphy, surgeon

"I always sensed that there was this long-held misconception that female surgeons are a bit weaker or have less endurance than men," says Toni Zhong, a plastic surgeon at Princess Margaret Hospital in Toronto.

The gap also results in fewer female mentors. "We go into surgery partly because of role models that we've found," says Zhong, adding that she found very strong ones in plastic surgery, a more female-oriented specialty.

But a large part the problem is that finding work-life balance is difficult in a field that asks you to drop everything at the beep of a pager.

Dr. Kirsty Boyd, left, and Dr. Carolyn Nessim are surgeons at the Ottawa Hospital. (CBC)

"The lifestyle of a surgeon is a difficult one, and a lot of women, especially those who want to have a family, shy away from that, because of the demands it makes on you and the amount of time it takes you away from your family," says Kirsty Boyd, a plastic surgeon at the Ottawa Hospital who's also featured in Keeping Canada Alive. She's the single mother of a 13-month-old — and the daughter of a surgeon.

One of the female trailblazers featured in the CBC program is Dr. Joan Murphy, a surgeon and gynecological oncologist in Toronto.

"My job has cost me and my family a great deal," she says. "And I just hope they forgive me for the days that I wasn't there. But it's who I am, and I hope it's been good for them in as many ways as it's been difficult. But I love my job. And that is such a privilege."

Carol Herbert is a professor of family medicine at Western University in London, Ont., and president of the Canadian Academy of Health Sciences.

"We've found in our research that gender does matter, that when you unpack it, there are special issues for women," says Herbert.

Those challenges limit the pool of talented physicians surgery can draw from, so the field isn't necessarily getting the "best and brightest," says Herbert. "We need people to go into disciplines like neurosurgery … we need to make those attractive, to make it possible for people to do that and not give up their lives."

And it doesn't just affect women — the younger generation of men are also seeking a balance and time with their families, says Herbert.

That culture shift may be coming: The U.S. has limited how many hours residents are allowed to work, and Canadian provinces are also starting to reduce the length of shifts.

"Everybody is sort of accepting that it's normal to want to spend time with your family, and it's actually abnormal to not see them grown up," says Zhong. "I think we'll see more women go into surgery as a result of things like that."