Parshas Metzora (5774)
Did you ever wonder why it is that when we pray for a sick person�s recovery we usually use his/her mother�s (Hebrew) name, while for other rituals such as writing the names on the kesubah at a wedding, receiving an aliyah in shul, etc., we use the father�s (Hebrew) name. [So, for example, if a sick person�s name is Yaakov and his father�s name is Yitzchak and his mother�s name is Rivka, we pray for the recovery of �Yaakov ben (son of) Rivka�, yet when calling him up to the Torah, we say �Yaakov ben Yitzchak�.]
The Ben Ish Chai writes in Shu�T Torah Lishmah #399 that this custom is based on the Talmud in Shabbos 66b which quotes Abayei as saying that all amulets (for healing) should contain the mother�s name.
Some Talmudic commentators suggest that the reason we use the mother�s name and not the father�s is because we can never be certain that a person�s father is indeed his father. In fact, the Talmud in Chullin 11b states that the father�s paternity is only assumed based on the Halachic principle that Rov Be�ilos Achar Haba�al � the �majority� of sexual relations that the mother engages in are with her husband. However, we can be one hundred percent certain that his mother is indeed his mother. [This reason might not work so well today when we have DNA testing.]
The Ben Ish Chai himself offers an entirely different and novel explanation. He writes that in order to merit a speedy recovery, the sick person needs as many zechuyos (merits) and as few kitrugim (demerits) as possible. Generally speaking, a woman has fewer demerits than a man for three reasons: (1) a woman is exempt from all time-bound mitzvos (commandments), so that she has less obligations to mess up than men do. (2) One of the most difficult obligations to fulfill � which men have and women don�t � is the mitzvah of Talmud Torah, studying Torah in one�s free time, and most men fail in this area. (3) Men struggle with their ta�avos (hormonal drives and lustful desires) in a way that often leads to hotzoas zera l�vatalah (wasting the seed) � an issue that woman obviously do not have.
For these reasons, explains the Ben Ish Chai, when praying for a sick person, it is better to use his mother�s name, since his mother likely has more merits and fewer demerits than his father, and that will serve him in good stead. However, when calling him up to the Torah, we use his father�s name, as his lineage � as a Kohein, Levi or Yisrael � is determined by his father and not by his mother.
Another potential source for the custom of using the mother�s name when praying for a sick person can be found in a verse in Psalms (86:16) where King David prays to G-d to �save the son of your handmaid�.
The Rada�k, in his commentary to Psalms, writes that David mentions his mother (whose name was Natzeves bas Adael � see the Talmud in Bava Basra 91a) rather than his father here because before and after birth a child�s entire being is more deeply connected with his mother than with his father. She is the one who carries him inside her body for nine months, and after that she nurses him and takes care of him, and all this has a powerful spiritual impact on the child.
Judaism teaches that each individual has free will and is responsible for his own actions and decisions; nevertheless, a person�s ancestry and upbringing do have an important effect on one�s character, and a mother�s influence is particularly significant in this respect. Having recognized this, King David invokes his mother rather than his father when praying to G-d for salvation.
Rav Ovadia Yosef ZT�L writes that if one does not know the Hebrew name of the mother one may use the father�s Hebrew name instead. The Chazon Ish (oral ruling cited in Orchos Rabbeinu vol. 1 page 64) adds that one may also mention his surname.
If a person was never given a Hebrew first name, one can always pray using his/her secular name, as G-d surely knows who�s praying to Him, Hebrew name or no Hebrew name.
http://www.torchweb.org/torah_detail.php?id=307