Question:
BS''D
Can two first cousins get married?
Answer:
It is halachically permitted for them to marry each other because they are not considered ervah to each other, and this was done many times in past generations. However on a practical level there are those who say that it can be very unhealthy and dangerous to the children in a genetic way.
Best wishes
Sources:
Shulchan Aruch Even Ha’ezer 15-17