Crossing the Threshold: How Assent and Capacity Actually Work for a Young Adult
tl;dr: The Magic Birthday and the Conversational Test
A minor child actually cannot assent to a Power of Attorney. Under Oregon law, they must generally cross the 18-year-old threshold first. Once they blow out the candles and legally become an adult, "assent" comes down to a straightforward, conversational legal test to prove they understand exactly what they are signing.
The Age Requirement: Preparing at 17, Signing at 18
To clear up a common timeline point: when I tell parents to start the planning process when their child is 16 or 17, that is strictly for drafting the blueprints.
Under ORS 109.510, an individual must reach the age of majority -- 18 years old -- to have the legal capacity to independently execute a binding contract or appoint an agent. A minor cannot legally execute a durable Power of Attorney. If your 17-year-old signs the document, it is legally voidable and likely will be rejected by financial and medical institutions.
The strategy is to have the paperwork drafted, reviewed, and completely ready to go while they are 17. Then, on their 18th birthday, or shortly after, they formally sign the document to grant you that authority.
The Capacity Test: What Assent Actually Looks Like
Once your child turns 18, they have to demonstrate Legal Capacity to sign the contract.
Here is a massive distinction that trips up a lot of families: legal capacity is not the same thing as a medical diagnosis. A young adult can have Down syndrome, autism, or another developmental disability and still possess the required legal capacity to sign a document. The law does not demand a high IQ or a flawless understanding of complex financial vehicles.
To legally assent, the 18-year-old needs to demonstrate a baseline understanding of three core concepts in the when they sign:
The Action: They must understand they are signing a document that gives someone else the power to make decisions for them.
The Agent: They must be able to articulate who they are appointing and why they trust that specific person.
The Override: They must understand that they are still the boss -- meaning they can fire their agent or revoke the document if they change their mind.
How Assent is Measured in the Room
In practice, assent is measured externally through conversation.
When it is time to sign the documents, a notary public or an attorney sits down with the young adult. We do not give them a formal legal test. Instead, we have a casual conversation. I will ask plain-language questions like, "What does this paper do?" or "If you need help at the bank, who is going to help you?"
If the young adult can answer those questions -- whether verbally, through sign language, or via an augmentative communication device -- they have demonstrated the legal capacity to assent. They sign the paper, the notary stamps it, and the legal safety net is officially deployed.
If they cannot answer those questions, or if they do not comprehend what the document does, they cannot legally assent. At that point, the Power of Attorney is off the table, and the family must pivot to the formal protective proceeding route through the Oregon Circuit Court, typically a Guardianship for medical and personal decisions, and a Conservatorship for financial management.
The Reality Check
Assessing capacity is about finding out where your child's baseline understanding currently sits. Does your child currently communicate their preferences in a way where they could independently answer basic questions about who they trust to help them with their money or their doctors?
