The Happiness Code

This book confused me. An unhappy
man and his wife live with their
young son. The wife wants another
child. The man refuses to allow
the wife to have another child,
but he has a child with his
research co-worker. The baby is
given a happiness gene. The baby
never cries, not even when he
is severely cut or stung by a wasp.
But what is this story about? What
was the author trying to say?
And what did the ending mean?
I have no idea.