"You are a woman."
It just sounds strange and is likely connected with the fact that jsi acts as an a clitic - wants to be in the second position. And ty does not want to be there in the second position which is unstressed.
Even for questions we would use just "Jsi žena?" or "Ty jsi žena?" (and in very special unusual contexts "Jsi žena ty?"). Jsi TY žena? is also a possible question, but strongly stresses TY (Are YOU a woman?). It must be reflected in the pronunciation.