One of the most common questions couples ask about prenups is: “Can we include provisions about our future children?” The answer is nuanced. Some child-related provisions are perfectly fine in a marriage contract, while others are strictly prohibited.
Getting this wrong can undermine your entire agreement. Here’s exactly where the line is.
What You Absolutely Cannot Include
Let’s start with the hard boundary. Under the Divorce Act (federal) and Ontario’s Children’s Law Reform Act, decisions about custody (now called “decision-making responsibility”) and access (now called “parenting time”) must be made based on the best interests of the child at the time of separation. These decisions cannot be predetermined in a prenup.
This isn’t a technicality. It’s a fundamental principle of Canadian family law. A child’s needs, circumstances, and best interests can’t be predicted years or decades in advance. A clause in a prenup that says, “Mother gets primary custody” or “Father has weekend access” will be struck down by any Canadian court. Including such clauses can damage the credibility of the rest of your agreement.
Similarly, you cannot predetermine child support amounts in a prenup. Child support in Canada is calculated using the Federal Child Support Guidelines, which are based on the paying parent’s income and the number of children. Parents cannot contract out of their obligation to support their children.
What You Can Include
While custody, parenting time, and child support are off-limits, there are several child-related provisions that a marriage contract can legally address:
Education funding: You can agree on how education costs will be shared, including private school tuition, extracurricular activities, and post-secondary education savings (like RESP contributions). This doesn’t replace the child support obligation, but it addresses expenses that go beyond basic support.
Religious and cultural upbringing: You can express shared intentions about how children will be raised in terms of religion, culture, language, and values. While courts may not enforce these provisions strictly, they can serve as evidence of shared intentions.
Career sacrifice compensation: If one partner plans to reduce their career involvement to care for children, the prenup can specify financial recognition for that sacrifice. This is one of the most practically important child-related provisions and is highly relevant to spousal support considerations.
Financial planning for children: You can outline how costs related to having children will be managed during the marriage, from maternity/paternity leave planning to childcare costs to RESP contributions.
What About Child Support Add-Ons?
While you can’t set basic child support amounts (those are governed by the Federal Child Support Guidelines), the Guidelines do contemplate “special or extraordinary expenses” under Section 7. These include childcare costs, health insurance premiums, extraordinary education expenses, extracurricular activities, and post-secondary education costs.
A marriage contract can address how these Section 7 expenses will be shared between partners. For example, you might agree that private school tuition will be split proportionally to income, or that both partners will contribute equally to a child’s RESP up to a specified annual amount. These provisions don’t replace the Guidelines. They supplement them by creating additional clarity around expenses the Guidelines don’t fully address.
Why Children Change the Prenup Equation
Having children fundamentally alters the financial dynamics of a marriage. One partner may leave the workforce. The couple’s expenses increase dramatically. Career trajectories diverge. Pensions and retirement savings are affected. A prenup that was fair for a childless couple may not be fair for a couple with three kids and one stay-at-home parent. This is why many family lawyers recommend including review triggers in the original prenup: provisions that require both partners to revisit the terms after having a child. For more on how money conversations shape marriages, read The Psychology of Prenups: Why Talking About Money Builds Stronger Marriages.
Planning for Children You Don’t Have Yet
Most couples create their prenup before having children, which means they’re planning for a hypothetical future. That’s perfectly fine. In fact, it’s ideal. By discussing how children will affect your financial arrangement before the pressure and sleep deprivation of parenthood, you’re making clearer, more thoughtful decisions.
The key is building flexibility into the agreement. Rather than rigid provisions that assume a specific future, use conditional clauses: “If one partner reduces their work hours to provide childcare, spousal support terms will adjust as follows.” This approach anticipates change without trying to predict exactly what will happen.
Plan for your family’s future with a thoughtful marriage contract. Get started at I Do Prenup.
Frequently Asked Questions
Q: Can I include child custody in my prenup?
No. Canadian law prohibits prenups from addressing custody (decision-making responsibility) or access (parenting time). These must be determined at the time of separation based on the child’s best interests.
Q: Can I set child support amounts in a prenup?
No. Child support is calculated using the Federal Child Support Guidelines based on the paying parent’s income. Parents cannot contract out of child support obligations.
Q: What child-related terms CAN I include?
Education funding, religious/cultural upbringing, career sacrifice compensation, RESP contributions, and childcare cost-sharing are all permissible.
Q: Should I update my prenup after having children?
Strongly recommended. Having children changes the financial dynamics of a marriage significantly. You can amend your marriage contract at any time with mutual consent.