Emancipated Children
Most people understand that both biological parents remain responsible for the financial support of their children until they become adults and that legally adopted children also fall into this category.
Many mistakenly assume, however, that their support obligation automatically ends when the child turns 18. For several reasons, this may not be the case.
It is when a child becomes "emancipated" that the parents no longer are legally bound to support that child. A child becomes emancipated before age 18 if that child marries, joins the Armed Forces, or otherwise leaves school, moves out of the house voluntarily, and becomes self-supporting. On the other hand, a child's emancipation may wait until much later than age 18 if that child remains a full-time student in good standing at a college or trade school, generally including a four-year college degree. (The terms "full-time", "good standing", and "trade school" sometimes need further defining and clarification.)
Most of the time, emancipation doesn't automatically happen; a court order (which may be entered by consent) usually becomes necessary to end a support obligation.
In unusual cases, some of these general rules may not apply. If you have genuine reason to believe that yours may be one of these unusual cases, you may want to consider obtaining competent legal advice from an attorney.