הלכה על כריתות 3:8

And [it] is practiced in every place and at all times. And women are not obligated regarding the circumcision of their sons (Kiddushin 29a); just the father - or the court when there is no father [present]. And one who transgresses this commandment and does not circumcise himself when he reaches the category of [those who can receive] punishments - which is thirteen year and a day - [each day, that he transgresses it from when he is grown and does not circumcise himself, violates a positive commandment. And if he dies and was uncircumcised by volition,] he is liable for excision. But the father is not liable for excision for the [lack of] circumcision of his son (Shabbat 133a), but he does transgress a positive commandment. And there is no positive commandment in all of the Torah the negation of which makes one liable for excision besides this and the slaughtering of the Pesach sacrifice (Keritot 2a).