1,493. Vows and Blemishes
Hilchos Ishus 7:6
Let’s say that a man tells a woman, “You are consecrated to me through this object on the condition that you are not bound by vows.” Marriage is only not effected if she is bound by a vow not to eat meat, not to drink wine or not to wear colorful accessories. If she is bound by any other type of vow, marriage is effected even if the man voices his objection to that type of vow. However, if his condition specifies that she is not bound by any vow, then marriage is not effected even if her vow is as insignificant as not eating carobs.
Hilchos Ishus 7:7
Let’s say that a man tells a woman, “You are consecrated to me through this object on the condition that you don’t have any physical blemish.” If she has one of the disqualifying blemishes, then marriage is not effected; if she has any other type of blemish, marriage is effected even if the man voices his objection to that type of blemish. The disqualifying blemishes include all the blemishes that render a kohein unfit to serve as listed in Hilchos Bias HaMikdash, plus body odor, excessive sweat, bad breath, a deep voice, breasts more than a handbreadth larger (about 3”) than those of other women, a gap of a handbreadth between the breasts, a scar from a dog bite, and a birthmark on her forehead – even if it is very small, close to the hairline, or has no hair growing from it. This kind of birthmark can disqualify as a condition for marriage but it would not disqualify a kohein from serving. However, if a birthmark has hair growing from it, or is as large as an isar (a small coin) even without hair, then it can disqualify both kohanim from serving and as a condition for marriage.
[Editor’s note: There are also disqualifying blemishes for men, the Rambam just doesn’t happen to be discussing those here. See, for example, Mishna Kesubos 7:10.]