MY CHOICE: Why do other people get so het up when I say I don't want to have children?

Are you too selfish to be a mother? Do you hate kids? You'll change your mind. Won't you be lonely when you're older? You just haven't met the right guy. Are you one of those career-obsessed women? Should you freeze your eggs in case? Don't you love me enough to have a child with me? Your mother must be so disappointed. Do you love your sleep-ins more than loving a child?

All of the words above have been uttered to me from a variety of people. Some I shrug off, but others are like lemon juice in a paper cut. And people feel they have the right to say these things to me simply because of my choice not to have children.

There's no gentle way to say I don't want to have kids. It's such a harsh statement. But it seems by refusing to breed I'm committing societal heresy. After all, mothers are soft and nurturing, and women who don't want children must be sharp and prickly. American comedian Rita Rudner once said, "My husband and I are either going to buy a dog or have a child. We just can't decide whether to ruin the carpet or ruin our lives."

I love jokes about it. Because no matter how I phrase it, I'm judged. And trust me, it's a lot more fun to say I prefer to "use my vagina for fun, not function" than to expose my vulnerabilities. For me, it all boils down to one thing: I've never felt clucky. Not before, not now, at age 39. I simply never saw children in my future. I didn't realise it would be such an unpopular choice. But what's the other option? Fake my enthusiasm and bring an unwanted child into the world hoping for the best?

It's important to point out that being child-free and childless are completely different situations. My heart breaks for women who long to be mothers, yet circumstances prevent them from having children. I have a friend who has admitted that her ovaries ache every time she sees a woman pushing a pram. I've cried with her. But being child-free means you have made a conscious decision not to have children. It is the last female taboo.

Most of the child-free people I spoke to for this story initially asked not to be named. All feared judgment. Some didn't want to be defined by their decision. One had never said it out loud. But after some gentle nudging they finally agreed.

Maha Obeid, a 41-year-old journalist from Sydney, says, "I feel like I'm waging a war against what society thinks and I'm tired of fighting. The first question people ask me is if I have children. It makes me really sad. And I'm Lebanese, so there's 10 times the judgment. It's like I'm not valued as a person because I don't have children."

Laura Bernay, a 55-year-old singer-musician from Perth, confesses, "I never woke up on weekends wishing for the pitter-patter of little feet. But I've never said, 'I don't want kids', to anyone. Instead I say, 'It didn't work out for us', just to avoid the judgment."

A recent study called "Childlessness in Australia", undertaken by Dr Bronwyn Harman, lecturer in the school of psychology and social science at Perth's Edith Cowan University, looked at why people choose to not have children. Of the 330 people surveyed, 250 were child-free and 80 childless. Focusing on the child-free, Harman found that the main reason they chose to not have children is that they didn't feel maternal or paternal. This was followed by thinking that it would ruin their lifestyle or career. Only six per cent actively disliked children.

"In the comments, the main reason for not having children is simply that they just don't want them," says Harman. "One analogy was that it's like a Lamborghini: you might want to drive one but you don't really want to own it." Yet it's not beneath male politicians to taunt Prime Minister Julia Gillard as "childless" and "deliberately barren", as if these were the most vile, bitter put-downs they could muster.

Celebrities who speak about it are far and few between. Recently, Dame Helen Mirren spoke about being child-free, telling Vogue UK, "Motherhood holds no interest for me. I have no maternal instinct whatsoever." And Australian singer-songwriter Ricki-Lee Coulter told the media recently, "[The entertainment industry] is not really the climate or environment to raise a kid in. Plus, it's not something I desire."

I can hear the tut-tutting now. "Oh my god, she's so selfish." No, she's just made a choice. When a child-free woman is called selfish, it's the mother of all insults.

"In my research, the one thing I hear more than anything else is that most people judge the child-free and immediately call them selfish," says Harman, who has three children herself. "I believe some parents are envious of the child-free."

Wait, what? If they are jealous of our child-free lifestyles, then why are so many hell-bent on convincing us to pop out a littlie? "The reaction from parents is that raising a child is full-time, stressful and hard work," Harman says. "But it's rewarding work. No parent said they would change back, but there is a feeling of envy, even if it is fleeting."

Anne Hollonds is a psychologist and mother of two children. "I've always questioned why people who choose not to have children are considered selfish. There's a large part of having children that is selfish. 'Because I wanted it for me.' 'It was something I had always dreamt about.' You have to own the fact there is an element of selfishness there."

Gillian Guthrie, author of the 2012 book Childless, explains the chasm in understanding that can occur between the haves and the have-nots. "The perception is that we're not tied down, we don't have real, nurturing feelings, we're not prepared to make the sacrifices mums and dads have to make ... we're ambitious and self-seeking," she says. "Now, I might be jealous of my colleague who has kids and who has to leave work early and arrive late when I'm expected to work through.

"It may well be that mothers and fathers find it hard to understand the lives we, the childless/child-free, lead, just as it's often hard for us to imagine what incessant family life is like. It's easy to be hostile to what you don't understand."

That hostility can be subtle, says Obeid. "I feel like I don't take up any space because I don't have children. Mothers with kids push in front of me at cafes like my time is less important than theirs. Friends with kids cancel at the last minute all the time. I understand that sometimes things come up with the kids, but if I'm in my car driving to their house when they cancel they don't even acknowledge that this is rude. Again, it shows that my time doesn't mean anything to them."

Harman goes a step further, saying that society "despises" child-free women because womanhood and motherhood are intertwined. "You are defined by the number of children you have and how well you mother."

Harman is about to throw the cat among the pigeons again with a new study she is currently undertaking, looking at life satisfaction. Who's happier: women with kids or women without? "The main factors I'm looking at are self-esteem, social support and resilience," she says. Whatever the outcome, it will be controversial.

Hollonds thinks it will be hard to measure, adding that no matter what a women's choice is, it seems she feels the need to justify it. "It's not enough to say, 'I didn't have children but I'm the CEO of a bank.' You also have to do volunteer work to show you are a nice, compassionate, non-selfish person."

Laura Bernay agrees. "I feel like I have to do this great, amazing thing so it's okay for me to not have kids: write a best-selling book, find a cure for cancer. Why can't I just be?"

Hollonds says it works both ways. "On the flip side: women who've chosen to stay at home and have children feel they have to justify they have a brain. It goes to the heart of how women feel they have to justify their existence."

She believes all this is changing, though. "I think [being child-free] is the last frontier of social stigma for private choices, especially for women. Child-free is almost the final taboo. It dawned on me that we used to talk about divorce like this. Divorce was seen as shameful. But it doesn't have that same stigma any more."

Although I'm very comfortable with my choice not to have kids, one thing I do think about - and, yes, sometimes worry about - is being lonely when I'm older. I have a great relationship with my parents and regularly go on holidays with them. However, having a child just to look after you when you're older is horrendously unfair.

I was recently reminded that not everyone has the close relationship I have with my parents. I'm in a loving relationship with a wonderful man (who also doesn't want to have kids), and I have a great brother and sister-in-law with two awesome nephews I love to bits. So why would I be lonely? They are my family, too. Right?

Harman says yes. "My study is under the umbrella of parenting and family. I say people who choose not to have children are still a family. Yet I've had lots of criticism about this. Why is it only the inclusion of children that makes you a family? You can have a familial bond with somebody that doesn't include a blood connection. Why can't it be with your partner and your partner's parents and brothers and sisters?"

Friends can be considered family, too. That's why, slowly, more child-free people are being brave enough to speak up and connect with like-minded people. Casey Pilcher, a 30-year-old truck driver, says men who choose not to have children are often dismissed. "I don't feel any emotion when handed a baby. Yet most of my family, well the ones who are aware, disregard my choice with an 'Oh, you'll change your mind.' " The isolation prompted him to set up Childfree Victoria, which organises outings.

Gillian Guthrie hosts lunches for the child-free in Sydney. "I had this overwhelming feeling that I didn't want to go to another social function where I might be asked about my parental status," she says. "At least we're able to enjoy the camaraderie of being in the same boat and not being outsiders in a community playing happy families."

In Melbourne, a group of child-free women who call themselves The Barren-esses have regular catch-ups, showing it's better to take the sting out of words like "barren" by using them. You can also buy T-shirts emblazoned with the words "Deliberately Barren".

I plan to wear mine with pride.

- Sydney Morning Herald