Types of relationship within which marriage is unlawful

Marriage may not possible if the parties are related, by blood, adoption, step-parent relationship or surrogacy.

Related by blood or adoption

A man may not marry his:

• mother
• adoptive mother or former adoptive mother
• daughter
• adopted daughter or former adopted daughter
• grandmother
• granddaughter
• sister
• aunt
• niece

A woman may not marry her:

• father
• adoptive father or former adoptive father
• son
• adopted son or former adopted son
• grandfather
• grandson
• brother
• uncle
• nephew
• great-grandfather
• great-grandson

Step-parent and stepchild relationships

A man may not marry his:

• former wife’s daughter or granddaughter
• father’s or grandfather’s former wife

A woman may not marry her:

• former husband’s son or grandson
• mother’s or grandmother’s former husband

except where:

• the younger person is 21 years of age or over at the time of the marriage and
• the younger party did not, before his or her 18th birthday, live in the same household as the other party and been treated by that person as a child of the family.

Surrogate Relationships

A man may not marry his:

• commissioning mother
• commissioning daughter
• surrogate mother
• daughter of surrogate mother

A woman may not marry her:

• commissioning father
• commissioning son
• husband or partner of surrogate mother
• surrogate son