If you are a male and dream of a boy, it could mean several things.
1) You may have seen dream imagery of yourself as a child boy.
2) You may have dreamed of your sibling.
3) If you are father, the image may be of your son.
4) If your girlfriend or wife has a male child, then this image could be him. If you had no knowledge of fathering a boy, then you might be curious enough to do your own investigations.
5) There could be a boy in your waking life, who has influenced you enough for you to remember him and dream about him. This boy can be a relative, neighbor or anybody.
6) The boy could be an invented image to remind you to help and be kind to the younger and vulnerable.
7) The boy can be your inner child, or the neglected part of you with needs that cry to be addressed. This boy remains a part of you and may appear in your dreams occasionally. Your female partner/ girlfriend/ spouse may be able to understand this and see this boy when she dreams of you.