Why Is Biology Not A Tie-Breaker in Child Custody Cases?
Child sitting beside a man

Why Is Biology Not A Tie-Breaker in Child Custody Cases?

Should the biological parent always be given preference over other guardians regarding custody?

In BJT v. JD, 2022 SCC 24 [BJT], the Supreme Court of Canada found that judges are not obligated to use biology as a tie-breaker when two prospective custodial parents are otherwise equal (para 87).

Biological Father

The biological father in BJT was unaware that he was the father when the child safety authorities took the boy away from his mother when he was 6 years old because the mother couldn’t care for him.

There were reports of the father abusing the mother and her elder son from a prior relationship (the child’s half-brother).

Despite this, the father was permitted to spend time with the child under his supervision and worked with specialists to enhance his parenting and interpersonal skills.

The Grandmother

The boy’s mother and maternal Grandmother moved in with them when he was a little. During his early years, she looked after him and supplied for his financial needs.

She was asking for recognition as the youngster’s legal parent at the hearing since she had taken on the role of a foster parent following Prince Edward Island legislation after the boy was brought into custody.

The hearing judge rules in favour of the Grandmother:

Even though the child’s requirements might have been met equally by either parent, the judge found that the Grandmother’s care was in the child’s best interests since she would foster his bonds with his extended family more successfully.

She would arrange for the boy to visit his father in Alberta and keep in touch with his mother and half-brother in Prince Edward Island, even if the child’s father was unwilling to make the same arrangements.

Appealing Defence of the Father 

The father, in the appeal, brought up the “parental presumption principle,” which stipulates that a biological parent should be favoured over a non-parent in circumstances where all other factors are equal, or the non-parent is slightly superior.

The Court of Appeal also reached the same decision, stating that the child should live with the father.

Grandmother Wins at the Canadian Supreme Court

The Grandmother then appealed to the highest court in our nation. The “parental presumption theory” should no longer be taken into account when deciding on child custody disputes, according to the Supreme Court of Canada.

When the hearing judge’s decision was upheld, the Grandmother ultimately received custody of the kid.

Does biology win out in the end? No.

In the 1985 Supreme Court case, King v. Low, custody was granted to adoptive parents over the child’s biological mother due to the youngster’s stability and relationship with their adoptive parents. This decision rejected the presumption that children are better off with a biological parent.

The court determined that, besides the security that comes from knowing your “roots,” biology is not a relevant consideration in child custody disputes when alternative options, like access or parenting time, will give the child the same links.

According to the BJT case, a child can have an equal level of attachment to people who are not their biological parents and the same level of ability to care for them (para 104).

Regulation of Child Custody

The child’s best interests must be considered while deciding who gets custody. Although a judge may take biology into account, it is one element of a highly contextual and fact-driven assessment.

According to Section 16(2) of the federal Divorce Act of Canada, “the court shall pay primary attention to the child’s physical, emotional and psychological safety, security, and well-being” while making parenting or contact orders.

Our province and territory have similar laws. The Family Law Act of British Columbia’s Section 37(2) lists the criteria that must be considered when making decisions of this nature. 

These considerations cover the child’s emotional health, physical condition, and opinions, if applicable, in addition to the parties’ ability to care for the child and any potential consequences of family violence on any future arrangements. 


The court’s ruling means that when deciding child custody cases, judges can no longer consider a parent’s biological sex as a determining factor. This is a noteworthy change from the previous status quo, where biology was often seen as the deciding factor in child custody cases. The new ruling is seen as a victory for equality, as it ensures that both parents will be treated equally in the eyes of the law.

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Disclaimer – The information contained herein is of a general nature. It is not intended to be legal advice and it is not intended to address the exact circumstances of any particular individual or entity. You should not rely on or act upon such information without receiving appropriate professional advice and without a thorough examination of your particular situation.