There's no bias in the selection. The girls are getting knocked back in pretty much the same ratio as the boys. (IE if the applicant group is 15% female only 15% of females are getting through to the hold file). A good operator is a good operator and that's what every pilot involved in the selection process is trying to assess.
Qantas have been upfront about trying to encourage more women to seek careers across the board. It's not just pilot positions although that was what the forum was about a few days back.
Where I reckon they're missing though is they're mostly preaching to the converted. Most girls at those forums are likely to have already chosen an aviation career or be thinking very seriously about it.