The Creation of the Humanoids [1962 - USA] sci fi

Many years after a nuclear war destroyed much of human kind, the survivors have created a new society where much of the work done by artificial beings referred to derisively by humans as "clickers". Humans are producing fewer and fewer children and are less than a year away from having more artificial beings than humans. Most vociferous about the evolving situation is the Order of Flesh and Blood, an organization that is out to ensure that humans remain dominant. Among them is Capt. Kenneth Cragis who becomes very concerned that his sister Esme has formed a relationship with one of the artificial beings. He quickly forms a close relationship with Esme's friend Maxine Megan. Soon, they learn a great secret that affects them both directly.