IN NS, there is not age of consent, though we do have an age of majority.
Some provinces that do have legislated age of consent
a physuicians needs to be mature enough, both emotionally and intellectually, to understand benefit/harm ratio and degree of risk
if the decision is in the minor's best interests, then it is easier to give control to the minor. Courts, whcih can be paternalistics will demand a higher level of maturity if the choice is more dangerous, and even moreso for refusal of treatment. In some provinces, minors can only make choices that are in their best interests
make choices very specific. maturity is tailored to the choice being made.
If a decision being made is significant and an adolescent isn't deemed mature enough, then you go to the parents. However, you definitely can't discuss prior decisions for which the minor was deemed mature.
Minors can't have sex with anyone two years older than them. Child wlefare legislation is in place to protect young children at risk of sexual abuse. Doctors are not a part of the legal system, so we don't need to report a relationship between a 13 year old and 18 year old, unless there is evidence of harm that requires protection.