Tony Abbott, the Australian opposition leader accused of misogyny by the country's prime minister, Julia Gillard, in a recent blistering speech that went viral online, has now accused the Australian government of being one that "lacks experience in raising children". Considering Gillard was previously described by the conservative senator, Bill Heffernan, in 2007 as being "deliberately barren", it seems fairly likely that Abbott's remark was not directed at "the government", but at Gillard herself, particularly as Gillard's cabinet contains members with "several children".

Perhaps one of the reasons the continuing spats between Abbott and Gillard are getting so much attention is that Abbott says out loud what many think about childless women: that our inexperience as mothers means that we're not really qualified to have an opinion on anything. "You'd understand if you had children" is the unspoken thought.

But why is this? When did being a mature adult woman equal being a mother? When did woman and mother become interchangeable terms?

The gift of humanity, and what makes it possible for us to live in society with people other than our blood relatives, is empathy. Empathy means literally "feeling into" – it's our ability to emotionally put ourselves into other people's shoes. Empathy is what makes civilisation possible and a person without empathy is considered to be a psychopath.

It is not necessary to be disabled in order to empathise with the challenges faced by disabled people and, similarly, disabled people are similarly capable of empathising with challenges faced by non-disabled people. Or not. Each individual's empathic capacity varies, like all human attributes, and develops differently depending on their environment and experiences throughout life. Therefore, while some people are capable of feeling into another's world with ease, others may have no more than a basic working capacity, as it would appear Abbott does from recent exchanges. But then again, he may be playing the misogynist as a political manoeuvre.

So just where does the idea that childless women are incapable of understanding the challenges of parenting come from? After all, we too were children once, and many of us have children in our lives, and even work with them.

Our culture has always feared the childless woman; she's a destabilising and potentially radical figure. Once upon a time, there weren't that many of us, and so we could be vilified as witches (while consulted as healers). But among the generation of women currently aged between 40-50 (what I think of as the shock absorber generation for the sexual revolution) one in five are reaching the menopause without having had children. This is double what it was a generation ago – and while some have freely chosen this and call themselves "childfree" there are many women, myself included, who are childless by circumstance.

As there have never been so many women in our culture not involved directly in child-rearing, we are looking at a challenge of how we define what it means to be a woman if you're not a mother. It's no longer acceptable to vilify one in five women – it just won't wash, as Abbott is finding.

Gillard tells of a joke she shared with Barack Obama: "I tell him, 'You think it's tough being African-American? Try being me. Try being an atheist, childless, single woman as prime minister'." Ultimately, whether Gillard is a good prime minister does not depend on her childlessness, it depends on her leadership.