That is a very hard question because it depends on the parents and not all children are the same. I think if parents give them a pet as a gift then they might [be(come) / make them] happy.

That is a very hard question because it depends on the parents and all children are not the same. I think if parents give their child a pet as a gift then they might be happy./ OR I think a pet would be a good gift to give a child.