The only reason why there is minority of female teachers in Buddhism is that it reflects the society in which we live. This has nothing to do with Buddhism at all.
If we had spiritual teachers in the society of the amazons in the hellenic world, these teachers would be female and the discrimination would work the other way around.
So in a world dominated by the male gender, teachers emanate as male.
Agreed 100% with you hope rainbow. This is not the issue of Buddhism as a religion or the holy teachings passed down by the great Buddha, it is more of the society structure.
Gender is not the main concern for Bodhisatva and highly enlightened lamas like the Dalai Lama. They will emanate in the form that will be most beneficial and effective to spread Dharma to the people in that particular place and society. Buddhas even emanated as non-human if that will help us.
Seems up till now, the most effective human form a Dalai Lama to take is a male form, he'll continue in this but if in future, a female form will be more effective, I'm sure he'll emanate in that too. Perhaps HHDL will emanate in more than one body in order to cater for different needs and conditions...
We can never really know for sure... que sera sera...
