Utah Saints

So I'm reading a book called Under the Banner of Heaven by a guy called Jon Krakauer. It's about Mormon fundamentalism, polygamous marriage, rape of teenage girls and their subsequent pregnancies, incest, abductions and murder. All pretty scary stuff. Mainstream mormons call themselves Saints, hence Utah saints, something I never knew. I have only read the first quarter but so far I have learnt that:
* polygamous mormons make up only 1% of the whole religion. They reside mainly in Northern Arizona
* Girls are often married into arranged marriages between the ages of 13 to 16
* There is a phenomenally high birth rate and girls start having children from the age of 13 in some cases
* It is illegal to have sex except when a girl/woman is ovulating, even if they are married
* Polygamy is illegal in all 50 States but this is often got round by not having a legal marriage ceremony

Scary