I asked my wife's thoughts on this. Here's some good wisdom from her IMO:
"If a woman is developing a curriculum, and is being honest and Biblical, she should only be developing it for women from the get-go. If a man happens to learn lessons from this kind of curriculum in passing, then it would be fine to teach about it in Sunday School as the woman was writing to other women, and not usurping authority. It's a case of one Christian building up another.
On the other hand a woman who develops a curriculum, and from the outset purposefully makes it for men and women has already usurped teaching authority and this curriculum should never be used by anyone."
I often find myself learning things from Rachel Jankovic, or Rebekah Merkle. Both of their intentions are not to teach men, but they are still wise women with salient advise.
"If a woman is developing a curriculum, and is being honest and Biblical, she should only be developing it for women from the get-go. If a man happens to learn lessons from this kind of curriculum in passing, then it would be fine to teach about it in Sunday School as the woman was writing to other women, and not usurping authority. It's a case of one Christian building up another.
On the other hand a woman who develops a curriculum, and from the outset purposefully makes it for men and women has already usurped teaching authority and this curriculum should never be used by anyone."
I often find myself learning things from Rachel Jankovic, or Rebekah Merkle. Both of their intentions are not to teach men, but they are still wise women with salient advise.