Sadly, it is the attitudes of many soldiers who think women don't belong in the combat arms that so many have left, and so few join. I can't think of a single female infanteer who has not been the victim or bullying, harrassment, sexual overtures from fellow soldiers, or various other forms of mistreatment. I know several that have quit because they were bullied into doing so. While women have to work harder in order to be successful in the combat arms, the men who are just as weak are given a fair shake right from the start. Despite all our attempts at PC-ness, gender integration and the like, it's the unfortunate lingering sexism that keeps a lot of the women away from such trades.
Fifty years ago, women weren't allowed to serve at all. 100 years ago, only white men could serve. The same tired arguments about group cohesion, and lack of "natural" agression have been used to exclude every minority group imaginable for centuries (Asians, homosexuals, women). It is only when people open their eyes and realize that EVERYONE has something to contribute, no matter what they're packing in their underwear. Some people can stick 200 pounds on their back and run a hundred miles uphill. Others make fantastic shots, while others can sit still in an OP for the better part of 2 days without moving or uttering a sound. I've seen plenty of male infanteers who are such bad shots that they couldn't hit the ground if they fell on it, and others who can't walk quietly, or move tactically at all. So, you make those guys your MG #2s, or your frontline assaulters. No one has said they can't serve, or that men have a genetic disposition to be loud, and could never do reconnaisance because they're too big and awkward. It's a ridiculous argument. People have different strengths and weaknesses, and should be employed with this in mind.
Women will continue to quit the combat arms in droves, or refuse to join in the first place until the mysoginistic attitudes that have made the CF such a hostile place for women remain.
Mo-litia; you watched me walk about a kilometre out of the field on a broken ankle, and you think women aren't tough? Not to mention, if you think women are caring and nurturing, try putting a baby in front of me. The thing would find itself starving and filthy before long. I certainly have no maternal instinct, nor some kind of intrinsic knowledge about child-rearing, just as men aren't born with a C7 in hand and the instinctual knowledge of how to dig a level 6 entrenchment.
Finally, you want to argue different standards? There are not, in fact, only 2; there are 10. Changes for men and women in every age group. This is ageist; as a 50 year-old corporal should be able to compete physically with a 17 year-old corporal, right?