From the article: ...as polygamy began to be phased out...The scientists' study confirmed their expectation that a moratorium on Mormon polygamy...
One other note: Good way of putting it -- "phased out" -- vs. a so-called Mormon "moratorium" (suspension of activity) didn't happen in 1890...yet another Mormon myth. C. Carmon Hardy, in his book Solemn Covenant, documents over 200 additional "plural unions" in his appendix (by name, dates, etc.) These occurred between 1890 and 1910...and were approved by Lds general authorities as they had to be properly solemnized. Often the couple would head for Mexico, leaving a previous wife or wives behind while the husband had yet another honeymoon.
My great grandmother who was catholic had 18 children. One day I must post the family picture. It’s hilarious. My poor great grandmother looks like tired worn out while my grandfather sits in his chair proud as a peacock with all his children around him.