If a child answers the door, we should ask to speak with his parents. This shows respect for their headship. (Pr 6:20) If the child invites us to come in, we should decline. If his parents are unavailable, we should return at another time.
If the child is older, perhaps in his mid-to-late teens, it would still be appropriate to ask for his parents. If they are not available, we might ask whether his parents let him choose his own reading material. If they do, we can offer him literature and perhaps direct him to jw.org.
When making a return visit on a youth who has shown interest, we should ask to meet his parents. This will allow us to explain our purpose in calling and show them the trustworthy and reliable advice found in the Bible for families. (Ps 119:86, 138) Our showing respect and consideration for the parents will be a good witness and may give us other opportunities to share the good news with the family.