Just because a woman has a womb, doesn't mean she should have to use it.

That is the opinion of former Waikato University masters student Theresa Riley, and enough people agree so her research has been made into a book, Being Childfree in New Zealand; How couples who choose to not have children are perceived.

Ms Riley, 33, who interviewed 10 childfree couples in the course of her year-long research, said people did not have to justify the decision to have children, but couples who chose not to have children often faced cruel judgment for their decision.

"There's an assumption that if we're a woman, we want children, then of course we'll have them. We'll find a way to fulfil our hormonal desire."

The softly spoken Ms Riley is outspoken on the rights of women to choose their own life paths, but she is not a feminist.

On the contrary, she said the feminist movement had created an expectation that women could do it all – that they could be "superwomen".

"I think a lot of women don't realise they don't have to do it all."

Ms Riley, who knew in her 20s that she never wanted to have children, said pressure to procreate came from all quarters – family, friends, strangers – but now that she is separated the pressure had diminished from when she was married.

"It's actually easier when you're single."

She said it was "crucial" for people to discuss their childfree intentions with their partner early on in their relationship.

"It's actually difficult to find a guy who isn't interested in having kids.

"Maybe I'll wait 'til my child-bearing days are over."

Ms Riley spoke fondly of friends' children, but had no hangup about saying she liked being able to give them back, that she could not stand crying children and babies, and that holding someone else's baby did not interest her.

She dismissed the commonly held fear that, without children, she would be lonely in her old age: she said it was just as much a concern, if not more so, for parents who focused everything on their children, only to have their children move away from them when they grew up.

Ms Riley said although her book focused on couples who made the choice not to have children, it could be helpful for people who wanted children but for whatever reason could not have them, and as a sociology text.

"It reflects an aspect of New Zealand society and the way we treat each other."

Being Childfree in New Zealand is available through Amazon.com at a RRP of $81.