Boy
noun
A child of a man is no man, it is a boy.
おとこのこ
If you know the kun'yomi readings of both of these kanji you should be okay. You have two separate single-kanji words put together by a の. That's why it's the kun'yomi reading - they're separate.
まえにいる男の子は、おか田さんの子どもです。
The boy in front of them is Okada’s child.
おめでとうございます、お母さん。かわいい男の子ですよ。
Congratulation, mom. It's a cute baby boy!
あの男の子は元気が良すぎる。今さっきも叔母さんの頭に卵を二十個投げつけて、うまく逃げ切ったんだ。
That boy has so much energy. He just threw twenty eggs at his aunt’s head and managed to run away.