Can you marry your 1st cousin in the Catholic Church?

Catholic AnswerNo, no one may marry a first cousin in the Catholic Church. Canon 1078, paragraph 3 says that "A dispensation is never given from the impediment of consanguinity in the direct line or in the second degree of the collateral line." Thus, marriage between first cousins is a diriment impediment which renders the persons involved incapable of contracting marriage validly, and no dispensation is possible for this impediment.

from

Code of Canon Law, translation prepared under the auspices of the Canon Law Society of America, Nihil obstat: + Anthony J. Bevilacqua, J.C.D.; Imprimatur: Rev. Msgr. John F. Donoghue, Canon Law Society of America, Washington D.C.

Canon 1091

1. In the direct line of consanguinity, marriage is invalid between all ancestors and descendants, whether they be related legitimately or naturally.

2. In the collateral line of consanguinity, marriage is invalid up to and including the fourth degree.

3. The impediment of consanguinity is not multiplied.

4. If there exists any doubt whether the parties are related through consanguinity in any degree of the direct line or in the second degree of the collateral line, marriage is never permitted.

Canon 1092

Affinity in the direct line in any degree whatsoever invalidates matrimony.

Canon 1093

The impediment of public propriety arises from an invalid marriage after common life has been established or from notorious and public concubinage; it invalidates marriage in the first degree of the direct line between the man and the blood relatives of the woman, and vice-versa.

Canon 1094

They cannot validly contract marriage between themselves who are related in the direct line or in the second degree of the collateral line through a legal relationship arising from adoption.