Conditions of parental union

As soon as you and your spouse meet certain criteria, you’re automatically in a parental union.

These criteria have to do with

• your common children,
• the family relationship between you,
• your matrimonial status.

If you don’t meet all these criteria, you can also form a parental union by signing an agreement to that effect.

To be in a parental union, you and your spouse must first be de facto spouses, i.e. you must live together and present yourselves publicly as a couple.

You are presumed to be living together if you share the same dwelling and are the parents of the same child.

A parental union is formed when you and your de facto spouse become the parents of the same child. This applies only to births or adoptions that occur on or after June 30, 2025.

For example, if Adam and Eve had children with their former spouses before forming a blended family but have no children together, they are not considered to be in a parental union.

On the other hand, if Eric and Sophie had two children in 2018 and 2020, and a third in December 2025, they are in a parental union. The parental union regime provides for rights and obligations between the spouses; however, it does not change their rights and obligations towards their children.

Specific examples

Stephan and Julie adopted a child born in May 2025, but the child’s official adoption date is August 2025. They are considered to be in a parental union.

Marianne and Gabriel used a surrogate mother to carry their child. The child was born in September 2025. The couple is considered to be in a parental union; it makes no difference if the child is born of a surrogacy.

There is no minimum age to be in a parental union if the other conditions are met.

The rules governing the parental union patrimony vary when a spouse is a minor.

There can be no parental union between close relatives, for moral and physiological reasons. You cannot be in a parental union with your

• sibling,
• half-brother or half-sister,
• parent or child,
• whether biological or adoptive.

However, there’s no reason why you can’t form a parental union with certain members of your family. You may have a parental union with

• a cousin,
• a relative by marriage, such as the former spouse of an aunt or uncle, your ex-brother-in-law or your ex-mother-in-law.

To form a parental union, you cannot be in a marriage, civil union or parental union, whether together or with another person.

For a parental union to be formed, you must be

• single (including in a de facto union),
• divorced, or
• widowed.

You are also considered single if you have obtained

• annulment of a previous marriage, or
• annulment or dissolution of a previous civil union.

For example, Melanie’s current de facto spouse, Phillip, is separated from his former spouse, Julie, but is still married to her. Until Phillip is divorced from Julie, he and Melanie cannot be in a parental union. A person cannot be in two unions of any type at the same time (marriage, civil union or parental union).