Women decide not to have children for many reasons.

Whether it be career-motivated, a lack of maternal feelings or a concern for population growth's impact on the environment — it's often a carefully considered decision.

And we already know fewer women are having kids as each decade goes by.

Data from the Australian Bureau of Statistics shows the number of childless women in the 45 to 49 age group was at 14 per cent in 2006. That compares to 11 per cent in 1996, and 9 per cent in 1986.

But what does this choice of childlessness mean for women at different stages of their life?

Career-minded and carefree: Amy Gurd, 27

"I don't need to have kids to validate my life," 27-year-old Amy Gurd of Brisbane says with conviction.

Amy and her husband of five years, Brad, have chosen a childfree life and are considering protective measures like a vasectomy.

Amy is not shy about her decision, but is tired of the judgement she is constantly faced with.

"I'm kind of annoyed this is a topic of conversation. Women are judged for conforming or not conforming to this gender role of being caring mothers," she says.

Amy Gurd would rather the responsibility of a dog than a child. ( Supplied: Amy Gurd )

The PhD student researching criminology realised in high school being a mum wasn't for her. She plans to dedicate herself to a career and travel the world.

"I know there are certainly women who can manage both really well, but becoming a parent would significantly impact and delay mine and my husband's career," she says.

"I'm happy with just my husband. We have two dogs which is enough responsibility."

Amy says lying has become a tool of avoidance in social circles where she often feels the pressure to comply with society's idea of being a woman.

"We actually got to the stage where it was just easier to tell people that we can't have kids just so the conversation will stop.

"I am supportive of people having kids, but it's not reciprocated."

My kids would have been neglected: Natasha David, 43

Sydneysider and career woman Natasha David is relieved she didn't succumb to "baby pressure".

The 43-year-old writer has experienced several traumas in her life, including the suicide of her husband, who wanted children.

Natasha David, 43, knew she didn't want children from when she was very young. ( Supplied: Natasha David )

"If I had have had children because my husband wanted them, there would have been a long period where they might have been emotionally neglected by me while I worked my own stuff out," she says.

"I even had to give away my cats during a time because they weren't getting enough attention, it would have been horrific for a child."

Natasha had not completely written off having kids with her late husband, but wanted for them both to work on their own mental and emotional health before considering it.

"I felt it would be selfish to have a child against all the odds," she says.

"But I felt like society was thinking I was selfish for trying to improve myself before having kids."

Natasha has a vivid memory of her five-year-old self announcing she would be forever childfree.

"My aunties were all laughing and saying I will change my mind. I remember being very offended they said that, because I was very strong-minded.

"I don't like having people depend on me, and am quite independent myself, so I get quite impatient with those who are needy."

Natasha has again found love since her husband's passing, with someone who also doesn't want children.

As for a "kid fix", Natasha says she gets that from loved ones' families.

"Like the saying goes, it takes a village to raise a child, I am part of that village."

Helped raise siblings: Sally Arnold, 66

The oldest of five kids and treated as a friend rather than a daughter by her own mum, Sally Arnold took on a parenting role for her siblings.

That experience combined with a career she loved meant she had no interest in having children of her own.

Sally Arnold, 66, helped raise her four younger siblings. ( Supplied: Sally Arnold )

"Growing up I was like the mother, mum would confide in me and could be a bit of a victim as well, it was quite hard," 66-year-old Sally says.

"There were always kids around, I had no space; I shared a bedroom with two other sisters even when I went to university."

The Melbourne-based psychotherapist and former business development manager for the Australian Ballet says later in life the arts and her husband were enough.

Perhaps surprisingly, Sally never felt any pressure to have children. Her late husband Tony had children from a previous marriage, and her own parents weren't interested in grandchildren.

"Mum and dad, they were shocking grandparents (to my siblings' children). It was almost like impediment for my dad," Sally says.

As for societal expectations, Sally says the arts was the perfect space for carving her own path without judgement.

"You're working with gays, bisexuals, transsexuals, it's a world of all possibilities sexually.

"The world I lived in very much encouraged diversity."

She says not having children has given her the freedom to discover herself, including joining a Buddhist community and undertaking intensive study.

As for entering her more mature years childfree, Sally isn't concerned.

"You can't expect kids to be around when you're older.

"There are times when I am lonely of course … but then because I've done a lot of work on myself and I know I can't put it on others to help me through feeling lonely."

Not sure? Embrace the 'freedom of uncertainty'

Healthy Mind Project psychologist Talya Rabinovitz works with women in their 30s and 40s who don't want children but have anxiety around it.

"On the one hand they can see themselves being happy in life without kids. On the other hand, they're worried they're making the wrong decision," she says.

"[Some] women report wanting kids but cite social pressure as the main motivating factor."

Talya says there are also cases of clients regretting their choice.

"They reach their early 50s and said, 'I wish I'd just taken the risk and had kids; now it's too late'."

But she says those who are confident about being childfree typically report feeling a sense of fulfillment and freedom from other areas of their life.

For women who feel selfish for considering a childfree life, Talya says choosing not to have children is as valid as choosing to have them.

"There is, however, a real opportunity for these women to learn how to harness the power of uncertainty and the freedom that comes when you surrender to it.

"Women who I've seen do this, step into their lives with a sureness that they will be OK, no matter what happens."