Referring to a Parent by Name

It is forbidden to call parents by their first name and doing so is a violation of the commandment to “fear” one’s parents. (1)  This is true even if they are not present, (2)  and even after they pass away. (3)  One may use a parent’s first name if it is preceded with a title. As such, one may refer to one’s parents as “My master, [First Name],” “My father/mother, [First Name]” or even “rav [First Name],” if appropriate. One may also refer to oneself as the son or daughter of Mrs. so and so. Le'halacha we say that in the presence of one's parent, one should not call them by their name even if it is preceded with a title, only if one has to do so like when receiving an aliya.

(4)  When one is asked one’s name for an Aliya, one should respond with one’s name “ben Rav [Name],” “ben Reb [Name],” or “ben avi mori [Name].” So too, one who is asked what one’s father’s name or mother’s name is should say “reb” before saying one’s father’s first name and “marat” before saying one’s mother’s first name. (5)

The title one uses to refer to a parent may even follow their first name, if appropriate. In fact, many sages of the Talmud referred to their father as “[First Name], my father.” (6) One may tell someone that “I am the son or daughter of so and so,” as Rivka said “I am the daughter of Betuel” (7) though, even in this case, a title should be used. (8) 

One who has a friend with the same name as one’s parent then if it is a common name, one may call out his friend's name not in his father's presence (those who do so in their father's presence, have on who to rely on) if however, it is an uncommon name then one should change slightly his friends name when mentioning it, this is as long as the parent is still alive.

  (10) It is permitted to write a parent’s first name without a title, as is done when witnesses sign a get. (11) (12) One need not use a title when mentioning a parent’s name in prayer. One merely says “my father [name] ben….” (13) 

Even though there is no obligation of "fear" towards one father law, one is, however, one is obligated to display "kavod," honor, toward his father-in-law, therefore one should call his father-in-law with a title as a sign of respect, like one would call an elderly respectful person. 

Since this is a halacha to have "fear" towards one's parents, even if the parents allow their children to call them by their first name one should not do so since one cannot forgive "fear". however only in a case where the parents ask the child to call by their first name like in a case of a business where if the child says a title it would embarrass the father or disturb him then it would be permitted, but generally it is forbidden even if the parent allows one to do so. 

Adopted children are required to honor their biological parents.

1. Kiddushin 30b.

2. Taz, YD 242:4.

3. Rambam, Hilchot Mamrim 6:3; YD 240:2. But see Tiferet Yisrael to Kiddushin 1:7; Ben Ish Chai, Shoftim 5. Cf. Bereishit 28:4, 31:42, 32:9, 50:24.

4. Tosfot Yeshanim, Yoma 87a; Gra, YD 242:36; Beit Meir, YD 240.

5. Pitchei Teshuva, YD 240:2.

6. Birkei Yosef, YD 242:15. For examples of sages who used their parent’s first name along with a title, see: Me'ila 17b; Pesachim 112a; Gitin 14a; Bava Kama 70a; Sanhedrin 80a; Bechorot 26a.

7. Bereishit 24:24, 29:12.

8. Pitchei Teshuva, YD 240:2;

9. Rambam, Hilchot Mamrim 6:3; YD 240:2.

10. Taz, YD 240:5; Shach, YD 240:3; Igrot Moshe, YD 1:133.

11. Yosef Ometz 87; Ben Ish Chai Shoftim 4.

12. Emek Sheila, YD 67; Be’er Sarim 2:52.

13. Sefer Chassidim 800; Birkei Yosef, YD 240:4; Ben Ish Chai, Shoftim 5.

14. Sdei Chemed, Ma'arechet Chatan V'kalla.