"I love being pregnant and my body heals well, so why not? I will keep on doing it for as long as my body allows."
Like her, many surrogates volunteer multiple times. Most also keep in contact with the families they help create.
"These guys [the intended parents] start off as strangers, then they become friends, eventually they become family," says Janet.
"They are uncles to my kids, and I'm in my 'surro' baby's life for the long run."
These women agree that surrogacy is a life-changing experience, which may partly explain why they give up their time and put their bodies at potential risk.
"I cannot imagine life without kids," says mother-of-five Janet.
"My tubes are tied and I don't want any more, but I love the feeling that I'm able to produce this for someone who couldn't have it any other way."
Marissa says: "I think it's just bringing light back into the world. I'm creating a child for these gentlemen but I'm also creating a legacy."
Image caption Surrogates often stay in touch with the family they help create
Tough road
Yet the road to having a surrogate baby can be lengthy and tough.
Multiple rounds of IVF, failed embryo transfers and miscarriages are common.
"I was very, very sick during the pregnancy, so my husband had to cover for me. He was super-supportive and so were my kids," says Janet.
"In my case, my fiancé gave me a hard time - he never understood why I was doing this," adds Marissa.
Being from a small rural town, she also found it difficult to avoid criticism from neighbours.
"I got a lot of: 'How could you give up that baby?' 'Why are you sacrificing your family life for a baby that you won't bring home?'
"So if you want to be a surrogate, you need to stick to your guns. It's your body, your choice."
Criticism of surrogacy is not uncommon.
Within feminism, for example, there is a school of thought that views it as a form of exploitation of the female body.
Academic Katy Fulfer, from the University of Waterloo, conducts research into surrogacy and says even though surrogacy in Canada is unpaid it does not mean there is no exploitation.
"I think comparing surrogacy and prostitution is appropriate, as you have two forms of embodied labour that people are selling," she says.
"The fact that women don't get paid is problematic, because fertility here is a for-profit industry and everyone else gets paid. Why isn't the surrogate getting paid?"
Within the altruistic model, surrogates only get expenses reimbursed while agencies, doctors, lawyers and fertility clinics are paid a fee - making it an expensive endeavour for intended parents that may cost more than C$75,000 ($56,767; £44,600).
The model is highly regulated. A few years ago agency owner Leia Swanberg became the only woman ever to be charged under Canada's law governing surrogacy.
She pleaded guilty to failing to keep track of all receipts for compensation paid out to the surrogates at her agency and was fined.
There is currently a big push to change this legislation.
"As compensation is banned, even sending flowers to a surrogate could expose intended parents to criminal liability," she says.
A breach could lead to fines of up to C$500,000 ($378,450; £297,300) or a 10-year jail sentence.
"In truth, it would be good to have more relaxed regulations and not have to collect receipts, but it's not a big deal. We are not in this for the money," says Janet.
"I'm proud, very proud that I'm able to carry this child."
"You are making brand new parents," adds Marissa.
"I handed this baby back to them with joy, because this baby was never mine".
"Think of surrogacy as extreme babysitting. In the end, the baby gets to go home to its parents. There isn't much more to it than that."
Listen to the documentary "The Surrogates Club"