So the Old Testament never actually makes any comment about lesbianism. All the comments against homosexuality are directed towards men, specifically Leviticus 20:13:

"If a man lies with a male as with a woman, both of them have committed an abomination; they shall be put to death; there blood is upon them."

So technically (and strict orthodoxs tend to be big on technicalities) there is nothing wrong with a Orthodox Jewish Lesbian. So in this case following the letter of the law (that it would only apply to men with men) makes for a more permissive law then reading deeper into the rule from which you could generalize to both types of same sex couples. Granted it is possible that a lesbian couple would risk violating one of the many other rules on sexual behavior, but lesbianism itself would not be the problem. (One possible problem is that a lesbian couple would not create children directly from their union.)