Girls learning Mishna?

Igros Moshe (Y.D. 03:087):Girls learning Mishna? Concerning the issue that there are girl’s schools (Beis Yakov) that the staff or principals want to teach them Mishna. Rambam (Talmud Torah 1:13) rules according to Rabbi Eliezar (Sotah 20a) not to teach girls Torah but he distinguishes between the Oral Torah which he says is like teaching them obscenity and the Written Torah which is only problematic l’chatchila.Nevertheless Mishna is Oral Torah and our Sages have commanded us not to teach them and it is like teaching them obscenity. Therefore it is required to withhold this from them. Except for Pirkei Avos which is mussar and good behavior which should be taught to them with clear explanations in order to motivate them in love of Torah and good character.