These women are raising a child together. But they're not in a relationship.

‘You can choose your friends, but you can’t choose your family,’ goes the old saying, but for many people, their friends are their family.

Take, for example, Natasha Bakht, 44, and Lynda Collins, 42, the two Canadian best friends who’ve chosen to raise a child together — and made history in the process.

In February 2010, Bakht, who was single and in her thirties, gave birth to a little boy, Elaan, with the help of a sperm donor.

Her closest friend Collins was in the same boat – feeling the maternal itch but happily partnerless – and offered to be her birth coach.

When Elaan was born, he weighed just four pounds and 13 ounces thanks to a knot in his umbilical cord, which had restricted his oxygen and nutrient supply for nine long months.

He was a beautiful, seemingly healthy baby, but within six months signs of disability began to show and a neurologist confirmed large portions of his brain were dead.

"I remember, as we left that neurologist appointment, Natasha said to me, 'What kind of life is he going to have?' And I said, 'He's going to have a wonderful life. We're going to make sure of that.'," Collins recalled in an interview with CBC News.

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Now 7, Elaan suffers from a severe form of cerebral palsy that means he has no independent use of his limbs.

He also has asthma, epilepsy and in his early years often struggled to eat.

"I didn't expect to have a child with disabilities," Bakht told CBC.

"It just changes what you think your path with respect to motherhood is going to be. I wouldn't change a thing, but I needed Lynda to remind me of that and she did, over and over again."

Collins has been in Elaan's life since day one.

She was the first to hold him, would accompany his mother to almost all his medical appointments and eventually moved in upstairs.

When she began thinking about adopting a child, she had an epiphany:

"I suddenly had this feeling, why am I adopting a stranger when I have Elaan?

"We were already living as a family," she said.

Both Collins and Bakht are lawyers but their lack of romantic involvement complicated things.

Collins could not formally adopt Elaan and, in fact, noone in Canada had tried to have a similar arrangement legally recognised.

But after two years of hard work, a court awarded her with a declaration of parentage and a new set of birth certificates arrived in January.

"I'm not a single mum anymore. I have a partner in this journey and I'm so grateful for that," Bakht said.

"Co-mumma is how we refer to each other now."