Is a Talit valid if the Tzitzit were tied by a woman, child or gentile?
Halacha requires that the Tzitzit be affixed to the garment and its knots be tied "Lishma" meaning, with the intention that this is being done for the purpose of the Mitzva of Tzitzit. Although the Rambam held that this is not necessary, normative Halacha follows the view that one must affix and tie the Tzitzit with this specific intention in mind. The question arises as to whether we would also demand that the person tying the Tzitzit is himself included in the obligation of Tzitzit. Given that women, children and gentiles are not included in this Mitzva, should we disqualify them from tying the Tzitzit to the garment?
Maran rules that a woman may, indeed, tie Tzitzit, provided that she has the required intention, and we may trust her word that she had this intention. A capable child, too, may tie the Tzitzit to the garment, so long as an adult supervises and reminds him to have the proper intention during the tying. Once a child reaches the age of thirteen, he may tie Tzitzit even without adult supervision. A gentile, however, cannot tie Tzitzit; a Talit whose Tzitzit were tied by a gentile is invalid and may not be worn.
