Are Prenups Bad? Pros and Cons for Parents in California and Washington

By Kevin Luu, Co-Founder and Chief Learning Officer. Reviewed on 2026-09-30.

No, prenups are not bad. A prenuptial agreement is a written contract that replaces your state’s default property rules with rules the two of you choose, and for a parent with children from an earlier relationship, pre-marriage equity, or a large expected inheritance, it is often the clearest way to decide in advance what belongs to whom. The real downsides are cost, a hard conversation, and the risk that a rushed or one-sided agreement is thrown out by a court.

This guide is written for parents in California and Washington, both community property states, where the default rules are strong and the stakes rise quickly at a $750,000 to $3 million household income. It covers what a prenup can and cannot do, what makes one fail, a worked example, and the postnuptial version for couples who are already married.

Why the default rules matter more in California and Washington

In California, nearly everything either spouse earns or buys during the marriage while living in the state is community property, owned half and half, no matter whose name is on the account (Family Code 760). Property owned before the wedding, and gifts and inheritances received later, stay separate (Family Code 770). Washington works the same way at its core: property acquired after marriage by either spouse is community property unless it falls under the separate property rules (RCW 26.16.030).

That sounds clean. In practice, high-income W-2 households blur the line constantly. Pay goes into a brokerage account that held pre-marriage savings. Unvested RSUs granted before the wedding vest after it. A 401(k) funded for ten years keeps growing with new contributions. Each of these creates a tracing question that someone has to answer later, usually at the worst possible moment. A prenup answers it in writing while both people are calm.

The real pros of a prenup for parents

• Protecting children from a prior relationship. A prenup can say which assets are kept for your children and can require each spouse to sign a will, trust or other arrangement to carry that out (Family Code 1612(a)(4)).
• Keeping pre-marriage equity and savings clearly separate. You can agree how vested shares, unvested grants, and accounts that receive new deposits will be treated, instead of leaving it to tracing rules.
• Deciding life insurance ownership and death benefits. California lets the agreement cover who owns a policy and who receives the benefit (Family Code 1612(a)(5)).
• Planning for one parent stepping back from work. If one spouse plans to cut hours while the kids are young, the couple can agree how that affects property and support, provided the support terms meet the extra rules below.
• Saving the family a fight later. A clear agreement usually means a shorter, cheaper, less public process if the marriage ends, which matters most to the children.

The real cons, and what a prenup cannot do

• It cannot set child support or custody. In California, a premarital agreement may not adversely affect a child’s right to support (Family Code 1612(b)). Custody is always decided on the child’s interests at the time.
• Spousal support terms are fragile. In California, any spousal support provision, including a waiver, is unenforceable unless the spouse giving it up had independent counsel when signing, and a court can still refuse to enforce it if it is unconscionable at the time of enforcement (Family Code 1612(c)).
• It cannot waive your spouse’s 401(k) rights. Federal rules say an agreement signed before marriage does not count as spousal consent for retirement plan survivor benefits (Treas. Reg. 1.401(a)-20, Q&A-28). Your new spouse has to sign the plan’s waiver after the wedding.
• Cost and time. Two lawyers, full financial disclosure, and several rounds of drafts. For a family with equity comp and a prior marriage, expect weeks, not days.
• The conversation. Some partners hear “prenup” as “I expect this to fail.” Framing it as part of the estate plan for the children usually lands better, and it is also more accurate.
• Terms can age badly. An agreement written at 34 with no shared children may not fit at 45 with three. It can be amended, but only if both spouses agree in writing.

What makes a prenup fail in California

California sets specific conditions for an agreement to count as signed voluntarily (Family Code 1615). The court must find that the spouse it is being enforced against:

1. had independent counsel, or was advised to get one and waived it in a separate writing;
2. had at least seven calendar days between first seeing the final agreement and signing it;
3. if unrepresented, was fully informed in writing of the terms, their basic effect and the rights being given up, in a language they are proficient in, and signed a statement saying who gave them that information; and
4. did not sign under duress, fraud or undue influence, and had capacity.

An agreement can also fail if it was unconscionable when signed and, before signing, the spouse it is enforced against did not get fair and full disclosure of the other’s property and debts, did not waive that disclosure in writing, and had no adequate way to know it otherwise. The practical rules follow: start months before the wedding, give each person their own lawyer, and attach full balance sheets, including RSU and option grants.

Washington does not have a timing statute like California’s seven-day rule. Washington courts review premarital agreements under case law and look closely at whether the terms are fair to the spouse with less and, if not, whether that spouse had full disclosure, independent advice and real time to consider. The same habits that satisfy California (separate lawyers, full disclosure, no last-minute signing) are what protect an agreement in Washington.

Worked example: a remarrying parent in the Bay Area

Assumptions (illustrative): Priya, 39, is a scientist at a biotech company in South San Francisco with two children, ages 6 and 9, from her first marriage. Before the wedding she owns a $2,000,000 brokerage account of vested company shares, with no transfer-on-death beneficiary, which is her separate property. She also has a 401(k) she built before the marriage. Priya earns about $450,000 and her partner Daniel is a physician earning $650,000, so combined W-2 income is about $1.1 million. They plan to marry in 2026.

Those shares come from California’s intestacy rules (Probate Code 6401). Because the children are minors, their share would typically be managed under court supervision until they are adults. Her 401(k) does not pass under these intestacy rules. It follows the plan’s rules, and it would generally go to Daniel as surviving spouse unless he signs the plan’s waiver after the wedding, whatever the beneficiary form says.

With a prenup plus a matching estate plan, Priya can keep the pre-marriage brokerage account and its growth separate, direct it to a trust for her children with a trustee she chooses, have Daniel sign the 401(k) spousal waiver after the wedding, and use life insurance on her life to provide for Daniel instead of splitting the children’s assets. Daniel gets clarity too: what is shared, what is not, and what he can count on.

The prenup does the divorce half of the work. The will, trust and beneficiary forms do the death half. A prenup without an updated estate plan leaves most of the table above unchanged.

Already married? The postnuptial version

Most families we meet signed nothing before the wedding. A postnuptial agreement can still define separate and community property, but the rules are stricter. In California, spouses owe each other fiduciary duties in dealings between themselves (Family Code 721), so an agreement that benefits one spouse is reviewed closely. Changing the character of an asset, for example turning community property into one spouse’s separate property, is only valid in writing with an express declaration from the spouse giving up the interest (Family Code 852). Common triggers are a large inheritance, a startup grant, or one spouse leaving work to care for young children.

A short decision checklist

• Do either of you have children from a prior relationship? If yes, a prenup and estate plan together are worth serious thought.
• Does either of you bring more than a few hundred thousand dollars of equity, savings or a business interest into the marriage?
• Do you expect a meaningful inheritance or family gifts?
• Will one of you step back from work while the kids are young?
• Can you start at least two to three months before the wedding, with separate lawyers?

If the answer to the first four is no, the state default rules may be fine, and the effort is better spent on wills, guardians and beneficiary forms.

What to write down for your kids

Children rarely see the agreement. They do live with its effects. A one-page note explaining why you set things up the way you did (what you wanted to protect for them, and how you thought about fairness to your spouse) is the part that teaches judgment. As Kevin puts it: “Your kids will inherit your money. Will they inherit your judgment?”

Frequently asked questions

Are prenups normal for people with high incomes?

They are common when either partner brings significant assets, equity or children into the marriage. For a dual-income household in tech, biotech or medicine, a prenup is usually treated as part of estate and financial planning rather than a statement about the relationship. The more complicated the balance sheet, the more a written agreement tends to reduce later disputes.

Does a prenup protect assets owned before marriage?

Those assets are already separate property by default in California and Washington. The risk is mixing: adding marital pay to a pre-marriage account, or using community funds to pay down a separate mortgage. A prenup can set how growth, new deposits and unvested equity will be treated, so the separate character is easier to prove later.

Can a prenup protect me from my spouse’s debt?

It can set how debts are allocated between the two of you, including student loans brought into the marriage. It does not change what either of you owes an existing lender, and which property a creditor can reach is set by state law and depends on how the property is characterized. Treat it mainly as a tool for dividing responsibility between spouses, and ask your lawyer how it interacts with creditor rules.

Next step

If you are planning a wedding or already married with a blended family, list every account, grant and policy you own, mark which existed before the marriage, and take that list to a family law attorney and your estate planning attorney together. Our estate planning and family governance work starts from that same list. For related reading, see naming a trust as beneficiary of a brokerage account, domestic partner vs. spouse, and questions to ask an attorney about inheritance.

This article is general education, not legal or tax advice. The right agreement depends on the family’s full picture, and each spouse should have their own lawyer.

Written by

Kevin Luu

Co-Founder and Chief Learning Officer, Bright Advisers

Kevin has advised high-income W-2 tech and biotech families since 2015, and leads the education-first Age Five Family Office from Brea, California.

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