תחפושות ואיסור לא ילבש

1.    Is there a problem on Purim for men to wear women's costumes or vice versa, because of the prohibition against wearing clothing of the opposite gender?


2. In the Shulchan Aruch the Rema writes that the practice of wearing masks on Purim and wearing clothing of the opposite gender is not forbidden since the intention is only to have fun.(.( שו"ע, או"ח, תרצו, ח From this we can deduce that he was not against it, and in his book Darkei Moshe he also quoted Rabbi Yehudah Mintz who maintained that one does not have to be concerned about the prohibition against wearing clothes for the opposite gender since on Purim the intention is not to truly wear the clothing in the normal manner, nevertheless he adds that it is praiseworthy to be strict and worship HaShem in joy, and 'to be glad in trembling'.

The Bach however, in his work on the Tur, disagrees, because when one gender wears clothing normally intended for ornamental purposes of the other gender, this is prohibited according to Rabbi Eliezer Ben Yaakov, and all the authorities decide according to him, yet they maintain that it is better not to forbid it so that people won't come to wear such clothing on purpose. It is better that they should do it unintentionally even if it's really a prohibition. A person who fears G-d should instruct his family and anyone over whom he has influence to stay away from this practice however, and this will bring down a blessing to overc. ( יו"ד שם) The Mishna Berura also rules that it is not necessary to rebuke a person who wears mainly clothing of his own gender, with the addition of one piece of clothing of the opposite gender.      (משנה ברורה סימן תרצו ס"ק)

In summary it seems that those who are lenient have opinions to rely on, and one should not try to dissuade him and tell him that it is undesirable.  It is clear however that it is worthwhile being strict, as a manifestation of piety, and because there are opinions that it is a Torah prohibition.