In Canada, mature teens can be granted more autonomy and privacy

In Canada, a "mature minor" can have some autonomy and privacy. This article by Florence Ashley explains it:

"The concept of “mature minor” was adopted into Canadian law following a 1985 decision of the British House of Lords called Gillick. In Gillick, a conservative activist sued the local government for prescribing contraception to some youth under 16 without parental consent, as a matter of policy. The case went all the way to the highest court in England and Wales, which affirmed that doctors didn’t need parental consent to prescribe contraception to minors who are sufficiently intelligent and mature.

Soon after, Canadian courts began to cite the case and adopt its reasoning. It wasn’t until 2009, however, that it was fully enshrined in Canadian law.

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Because the law says that parents must exercise their parental authority “in a manner that is consistent with the best interests of the child,” they are supposed to respect the decisions of their mature children. This notably means that they—and teachers—are supposed to respect trans youths’ names and pronouns if they are mature minors, regardless of what they think about it.

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In Canada, medical practice typically assumes that mature minors have a right to confidentiality and some provinces have adopted laws that say so. According to the healthcare tribunal of British Columbia, a mature minor “has the same right to privacy as an adult patient.” This assumption is very important for minors seeking birth control and abortion, who often don’t want their parents to know. However, the question has not been comprehensively explored by courts.

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The mature minor doctrine applies to trans youth. Trans mature minors can make decisions regarding gender-affirming care.

They can also make decisions regarding their gender identity and expression, such as choosing their pronouns, name, clothing, etc. However, these decisions are more difficult to enforce than medical ones since there isn’t a clear, explicit and effective legal structure in place to govern non-medical decisions."

— Florence Ashley, How ‘mature minor’ laws let trans kids make their own decisions: Canadian law lets some youth make medical or legal decisions for themselves, but how does it work? Xtra, October 3, 2024

And this is why, Ashley says, some people argue that some 2023 anti-trans laws violate the rights of "mature minors": namely, Saskatchewan and New Brunswick's parental veto over the name and pronouns a child wants to use in school until the child turns 16. "Alberta is planning to adopt a similar law and supplement it with a ban on gender-affirming care for youth under the age of 16, among other things," Ashley writes.

While children (and adults on their side) can take a parent to court, this would cost money that the child typically doesn't have. Also, provincial governments can use the Notwithstanding Clause to override the "mature minor" dotrine.