In Ireland, marriage between first cousins is legal under civil law. Here is an overview of Ireland’s marriage laws concerning biological cousin unions.

Irish Law Allows Cousins to Marry

According to the Marriage Act of 2015, marriage is permitted between biological first cousins in Ireland without any prohibitions or limitations imposed. There are no civil laws barring cousins from marrying.

This allowance also extends to double first cousins, who share both sets of grandparents rather than just one. Despite their closer degree of kinship, Irish law does not prohibit double first cousins from marrying.

No Special Requirements for Cousins

Irish first cousins can marry under the standard marriage regulations. There are no extra requirements like genetic testing, medical screenings, or proving infertility imposed specifically on cousin couples.

Cousins have the same rights and follow the same marriage rules as unrelated couples under Irish law when marrying. There are no additional legal hurdles.

Cultural Views on Cousin Marriage

However, even though legally permitted, views on cousin marriage remain mixed across Irish society. Surveys show younger people are more open to it, but objections around potential birth defects and incest taboos persist.

Supporters argue bans excessively restrict personal freedom around marriage choices between consenting adults. But stigma remains present for some.

Rationale Behind Ireland’s Approach

By neither prohibiting nor promoting cousin marriage, Ireland’s law emphasizes individual liberty and choice for couples. It does not impose moral or genetic judgments, allowing people to make their own decisions.


In summary, Irish civil law places no restrictions on marriage between first cousins. Cousins have the same marital rights as non-related couples. But social acceptance fluctuates, so couples should expect mixed reactions from others.