When is an individual not responsible for their own behavior? What about groups? Committees? Executive boards?
A person who gets behind the wheel of a car after consuming ethanol is responsible for that decision. If we catch them, or they hurt someone, we put them in a cage(Sometimes, sometimes not). Because they are 'responsible' for their behavior.
Another pair of people consume ethanol and engage in sexual activity. Later we put one of them in a cage, because one of them is 'responsible' and one is not.
An adult is sometimes 'responsible' for the well-being and safety of certain children, but for some reason not 'responsible' for others. This one I can make rational arguments for, but they have a lot of basis in genetic competition in general, and eugenics in specific.
Also, I would prefer to address this question without bringing gender into it, because I hold every competent adult human to the same standards of behavior and maturity.
Regarding this ^^^ bit, I think it's necessary to write laws with that assumption.