I work as a merchant selling Mezuzos and Tefillin [i.e. Socher Stam]. The Parshiyos are supplied to me from various Sofrim which I choose. I was recently told by a customer that I should not be taking any Parshiyos of Tefillin and Mezuzos that are written by Bochurim being that they are not married, and it’s not right for me to sell them to the public. It happens to be that some of the Sofrim who supply me the Parshiyos are Bochurim who have completed a Safrus course and in general sell it to me for cheaper than a normal Sofer. Is there any real issue with this?
So long as the Sofer is over 18 years old or has a full beard, it is permitted for him to write Parshiyos of Tefillin and Mezuzos even if he is not married, and you may certainly sell such Tefillin and Mezuzos, unless there is a set custom in your community not to sell such products without explicitly telling the buyer. [As far as I know, especially amongst merchants, there is no set custom to not sell Stam of Bochurim, even though this is the policy of some Safrus Stores and Sochrim. Thus. it is upon the buyer to verify this if he desires and it is not the obligation of the seller to inform the buyer, unless they are very expensive Mezuzos or Tefillin, in which case the buyer assumes that they are of the most Mehudar status.]
Explanation: From the letter of the law, so long as the Sofer is over 18 years old or has a full beard, it is permitted for him to write Parshiyos of Tefillin and Mezuzos even if he is single. Now, although there are Poskim who record a Hiddur for the Sofer to also be married, aside from the fact that this is omitted by most other Poskim, even in their opinion it is a mere Hiddur and not a requirement. Accordingly, it is not your obligation to inform the buyer that it was written by an unmarried Sofer, although if he asks you must tell him the truth. Likewise, in communities in which it is standard practice of the Sochrim not the sell Tefillin and Mezuzos of Bochurim, then seemingly you must inform the buyer of this prior to selling it to him. Now, regarding the reason for there being a Hiddur for the Sofer to be married, this is because one who is married is often less troubled by forbidden thoughts relating to women then one who is single, and it is of utmost importance for the words to be written with holiness. We find a similar concept regarding the criteria of a Chazan for the high holidays, in which one of the criteria is that he be married, even though we do not find such criteria recorded regarding a regular weekday Chazan. This is similar to the Kohen Gadol which had to be married as being married saves one from sin. Now, just as regarding the high holidays the Poskim conclude that it is all dependent on how God-fearing the Chazan is, and a single young learned and G-d fearing Jew is to be chosen before a married thirty year old Chazan who is a simpleton, then seemingly the same should apply regarding Stam. Thus if you know this Bochur to being God-fearing then he would have precedence even over a married Sofer whose fear of heaven is in question.
Sources: See regarding Sofer being married: Kol Haramaz Tikkun 6; Mishnas Hasofer 1:1 in Yalkut Hasofer; Shevet Halevi 8:178-2 [does not agree with giving Kabalah of Stam to Bochur]; Piskeiy Teshuvos 39:1; See regarding choosing a married Chazan for high holiday prayers: Rama 581:1; Kol Bo 68; Elya Raba 581:15; M”B 581:13; See regarding requirement of age 18 or full beard: Admur 39:1; M”A 39:1; M”B 39:3; Minchas Elazar 4:57; Piskeiy Teshuvos 39:1 footnote 2; See also: Admur 37:3; 55:6; 128:49; 199:9 regarding Birchas Hamazon; 271:7 regarding Kiddush; M”A 271:2; M”B 271:3; Michaber E.H. 155:15 regarding Miun and 169:10 regarding Chalitza; See Avnei Nezer 516-517; Other opinions: Some Poskim rule Bedieved it is valid if written by a child above Bar Mitzvah. [Noda Beyehuda Tinyana 1; See Avnei Nezer 516-517]