The Right to marry and found a family is explained in these documents:

Legally Obligating Documents
Additional (San Salvador) Protocol to the American Convention on Human Rights in the Area of Economic, Social and Cultural Rights  (15)
African (Banjul) Charter on Human and People's Rights  (10)
American Convention on Human Rights  (17)
Arab Charter on Human Rights  (38)
Convention on Elimination of All Forms of Discrimination Against Women  (16)
Convention on the Rights of the Child  (8, 9)
European Convention for the Protection of Human Rights and Fundamental Freedoms  (12)
International Convention on Elimination of All Forms of Racial Discrimination  (5(d)(iv))
International Covenant Economic, Social and Cultural Rights  (10)
International Covenant on Civil and Political Rights  (23)

Standard Setting Documents
Beijing +5: Further Actions and Initiatives to Implement the Beijing Platform for Action  (60)
Beijing Platform for Action  (93, 274(e), 275(1))
Cairo Programme of Action  (4.21)
UN Special Session on HIV/AIDS (UNGASS) Declaration of Commitment  (54)
Universal Declaration of Human Rights  (16)