The US supreme court recognizes it as a fundamental right, fundamental rights are so important that the founders felt it was unnecessary to list them, and via listing fundamental rights you are via their very nature limiting them, for eventually you would have someone who tried to twist the right saying X is not really a right for it isn't listed in the 430 something rights.

The European Convention on Human Rights has an entire article (article 12) that declares you have a right to marry and create a family.

The UN Declaration of Human Rights has an entire article (article 16) that declares you have a right to marry and create a family.