Q. 1. What is the Church teaching regarding dating and marriage between cousins?
A. 1. First of all, I should point out that according to civil law, one is prohibited from marrying first cousins. As such, it includes the prohibition of dating for the purpose of marriage. Civil law also prohibits marriage to closer relatives such as parents, children (including adoptive), grandparents, etc...
On the matter of Canon Law, Paragraph # 1091 states:
§1. "In the direct line of consanguinity marriage is invalid between all ancestors and descendants, both legitimate and natural."
§2. "In the collateral line marriage is invalid up to and including the fourth degree."
§3. "The impediment of consanguinity is not multiplied."
§4. "A marriage is never permitted if doubt exists whether the partners are related by consanguinity in any degree of the direct line or in the second degree of the collateral line."
Under Canon Law, one is prohibited from marrying someone related by blood up to the 4 th cousin or 4 th generation such as one's great grandchild.
Under certain circumstances, one can obtain a dispensation to allow marriage within the fourth degree. Please contact your parish priest for information regarding to a dispensation.