Can my half-brother marry my daughter

Marriages between relatives - what's up? What is not working? And why?

A number of precursors to marriage are laid down in the Civil Code. In addition to principles such as the prohibition of bigamy, the marriage of relatives according to § 1307 BGB also belongs in this list. A marriage must therefore not be concluded in a straight line between blood relatives. In addition to the state ban, there are also canonical provisions that allow such a marriage to be annulled. Parents and children, grandparents and grandchildren and full or half siblings are legally excluded from marriage. If a relationship is to expire through adoption as a child, this prohibition still applies.

Borderline cases and exceptions

In contrast, the ban on marriage between persons in law in a straight line has been lifted. Nowadays, cousins ​​are allowed to marry just like uncles and nieces. Marriage is also possible without hesitation for step-siblings without a common parent.

It looks a little more complicated when it comes to adoptive relationships. Adopted children are legally considered to be related. The same rules apply to you as to siblings by blood. So they are not allowed to marry their adoptive siblings either. Such a marriage is possible if the adoption relationship is terminated.

If a marriage comes about that would actually violate a marriage prohibition, this is first of all effective. However, it remains contestable and can be annulled at any time through a marriage annulment procedure (§§ 1313 ff. BGB). An exception to this rule is the adoptive relationship.

Reasons for the ban on marriage between relatives

There are a number of reasons for the existing bans. First of all, they are moral. Above all, the relationship between parents and children, but also between siblings, should be fundamentally different from that between lovers. Mixtures here can also damage the psyche and social behavior. But there are also bare biological reasons. Hereditary diseases can be passed on more easily due to the close genetic relationship and predispositions to diseases can also emerge more frequently. In addition, there is a considerable risk of mental or physical disability in the case of children together.