Are you hand pollinating or relying on Mother Nature? I've had great luck pulling a male off and tickling the female flowers with it. You may try that if not. Flowers of unpollinated buds fall off eventually.

momma_s - your female are blooming, just not getting pollinated. You may have to hand pollinate, as sinfonian suggested.

EG

Thanks for replying, Sinfonian & EG.

The problem I'm having is that the females aren't even getting a chance to bloom. The unopened flower bud and base (ovum?) of the female are turning yellow.

Taking a look at the plants today, there are larger females that are growing, so maybe this was just happening with the first females that appeared? Have you noticed this before?

Oh. I am planning on hand pollinating if/when I get the chance. I don't want to take the risk!