 Fathers and mothers may react differently to the same behaviour in an infant, and the infant may react to the parents ’ behaviour differently depending on which parent performs it.
<fluency>  Fathers and mothers may react differently to the same behaviour in an infant, and the infant may react to the parents ’ behaviour differently depending on which parent performs it.
 Fathers and mothers may react differently to the same behaviour in an infant, and the infant may react to the parents ' behaviour differently depending on which parent performs it.