The biggest problem I have right now with this is "her". The 3rd person possessive and objective cases are identical for female ("her"), but different for male ("him" / "his").

So these 2 sentences flip "her" differently:

    It was created by her very quickly
    It was created by her very own child

I'm no NLP expert so if anyone has some ideas, please see this issue: https://github.com/Garrett-R/gender_bender/issues/2