TORONTO - The Liberals are losing another female cabinet minister this fall as the growing list of women leaving politics is sparking concern about gender balance in the Ontario legislature.

Mary Anne Chambers, minister of children and youth services, said Wednesday she isn't running again in the Oct. 10 election for unspecified health reasons.

"It was a very difficult decision because I'm not finished yet,'' Chambers said in an interview. "I still have things on my wish list, of what I want to get done before October, so I'll be working hard until the end.''

But with her imminent departure, the Toronto-area politician now joins the increasing number of women -- cabinet minister Marie Bountrogianni, Liberal backbencher Jennifer Mossop and NDP veteran Shelley Martel -- who are choosing not to remain in provincial politics.

The fact that she is following such women out the door of the legislature is just "purely coincidental,'' said Chambers, who was first elected in 2003.

While political rivals suggest Liberal women are leaving because they are worried about running on their record, others say it's a troubling sign politicians of all stripes need to make the profession more attractive for women.

With two kids at home and an equally busy spouse, Bountrogianni said she often found it difficult to juggle her various roles with midnight sittings at the legislature.

"Whoever forms the next government should take a very serious look at that because we won't be able to attract not only good women, but family-oriented men,'' said Bountrogianni.

"It's very difficult. If there was an easy solution, it would have been found by now.''

In her post as democratic renewal minister, Bountrogianni said she grappled with how to make politics more family-friendly. Now, she said it's incumbent on the next government to form a committee to study the issue and look at what other jurisdictions have done.

Rosemary Speirs, chair of the group Equal Voice, said the growing exodus of strong women from politics is troubling. Without a foundation of incumbent women, Speirs said it's going to be difficult to increase the number of women sitting in the legislature after Oct. 10.

"We are quite worried about it,'' she said.

"We were hoping to make substantial gains for women in this election. We thought we were building on a pretty strong base, particularly on the number of women in the Liberal party. When major figures leave, you worry about whether you can reach those goals.''

Women now make up 25 per cent of the legislature, thanks to a recent byelection. Speirs said her group had hoped to see that increase to more than 30 per cent.

But Lisa MacLeod, a rookie Conservative politician with a two-year-old daughter, said she fears there will end up being fewer women sitting in the legislature after Oct. 10 than there are now.