Sorry (well its been less important in the last several years, which I hate), but two of the biggest factors in hurting female teams is the ability to navigate (thats not luck, thats not being able to follow instructions or properly read a map for most legs), and the ability to drive a stick shift.
Huge, huge factors that eat up a ton of time on most seasons (even if the focus of the footage is tasks, they generally don't take the most time of a leg, though of course their are exceptions).
And frankly I don't understand why, yet in my own life I know more guys that learn how to drive stick then women, even in families where its the mom teaching the family to drive.
As for Dustin & Kandice we also have to remember that this team in both seasons didn't start out strong , with some serious errors that luckily didn't have any real impact on them (put but if done before equalizers could have killed them) things like driving an hour and a half to get 10 miles. The trouble they had in vietnam, of which an all male team is the only one that did worse.
But for all the complaining about physical tasks, is that their are usually choices, and options to help.
Take Maria & Tiffany, I beat every women in that hall was capable of ringing that bell.
Take Dustin & Kandice's near elimination in the boats in Vietnam, yet we have footage of an old women using one just fine herself.
Look at the salt task in season 6, Adam struggled, but hell Mary Jean gave it her all got in their and got it done.
In fact strength is general not a big factor in the race, skill and endurance are far, far more important.
Look at the climbing of the great wall, most racers wasted all their strength not actually figuring out how to climb it properly. Yet Jamie & Kelly flew over the top, doing it right. Their lack of skill with the bow was must likely what tired her out so that by the time she got the hang of it, she was already exhausted. My school everyone had to have some training in archery (go figure).
Between the ability to read maps, being able to drive, the next largest factor has been making poor choices. Tian & Jaree got eliminated due to taking a very passive task, one they don't have control over, it was exceptionally stupid, not that they were a good team, but they certainly had a shot. Hell not many teams that year were any good. What is exceptionally painful is watching women teams do poorly at tasks that are truly designed to not require strength, endurance or sports/outdoor skill sets.