First off, I usually refer to it as Extended Range Diving rather than Tech Diving. Extended in either time (requiring deco) or depth past recreational limits. As well as diving any overhead environment, may that be virtual (the beforementioned deco) or real (wrecks and caves).
There are plenty of women who do that sort of diving, and several who are quite well known for it. If you look hard enough you'll also find plenty of female instructors who teach that sort of diving. Many of them seem to prefer to keep a lower profile in public than their male counterparts, but they are there. Just have a look at NACD's or CDS' instructor base.
Look at some of the big explorations like Wakulla II and you'll see women being part of the crews and dive teams. Generally outnumbered by men, but they're there right among them.
Looking around my friends and usual dive buddies, there isn't much difference, really. None of them have intrest in doing extended ranges or overhead diving. Reasons are also the same: too much stuff to haul around, too much too plan, too high a risk, too expensive, and no good reason to do it in the first place.
With the latter I mean they all dive to see the wild life, and there is plenty (if not more) at a 100' than at 200' or 300'. They all love to dive (to) a shallow wreck, but have no inclination whatsoever to penetrate it. The idea of 1/2 an hour deco isn't appealing, nor is the black whole that marks the entrance to cave. Even those who took guided dives in cenotes and came back wide eyed and smiling have yet to show any intrest in getting a cave ticket.
Their reason for diving is perfectly available at 60', 100', so why bother.
The comparrison to skiing was a good one. Not everyone wants to take a chopper ride to a virgin mountain top, the majority of people are just as happy on the slopes.
The gear issue is a major one too, I believe, and one that may be the reason why more men than women pursue extended ranges: a lot of gear to buy, to clean and maintain, to learn to use and use, to haul around. When it comes to buying and fiddling with gear, male behaviour can reach extreme and worrysome levels.
One woman's Manolo Blanik is the next guy's Halcyon.
