- Question: [Tuesday, 17th Teves 5783]
We have only girls and my wife is two months pregnant, may we still Daven for it to be a boy?
No. After 40 days from conception you may only Daven for the physical and spiritual health of the child, and not for its gender due to it being a Tefilas Shav.
Explanation: The Mishneh states that one who Davens for a matter of the past is praying a Tefilas Shav, a prayer in vainm. The Mishneh then continues and states, as recorded in the Shulchan Aruch, that one may only Daven for a specific desired gender of a child up until 40 days from conception, when it is still naturally possible for the gender to change. However, past 40 days one who Davens for a specific gender, then his prayer is defined as a Tefilas Shav, a prayer in vain, as he is asking G-d to change nature being that the gender is already set in place. The Gemara then explains that although Leah Davened to change the gender of her fetus from male to female, this was done within 40 days from conception, or perhaps was a mere miracle which we cannot rely upon. Now, while the wording in the Mishneh and Shulchan Aruch do not make clear whether there is an actual prohibition involved in reciting such a prayer, and it is possible to explain that there is no actual prohibition but a mere discouragement, practically, many Poskim rule that it is actually forbidden to Daven for a matter of change of nature which is a Tefilas Shav. To note, that according to the Yerushalmi, one may Daven for a male child up until the time of birth, although we do not rule this way.
Sources: Tefilas Shav and that cannot Daven past 40 days: Michaber 230:1; Brachos 54a; 60a; Kaf Hachaim 230:2; Kitzur SHU”A 61:6 Poskim who prohibit a Tefilas Shav: Sefer Chassidim 794; Bechor Shur Shabbos 21; Kaf Hachaim 230:1; Or Hachaim in Chefetz Hashem Brachos 60a; Yabia Omer O.C. 35:11; Opinion that may Daven past 40 days: Yerushlami Brachos 9:3; See Likkutei Sichos Vol. 24 p. 34