50% greater birth rate than the UK is nothing to shout 'god bless america'
about when you consider that's compared to the population of the UK being 60,943,912 (July 2008 est.) and the US 303,824,646 (July 2008 est.)
https://www.cia.gov/library/publicat...ook/index.html
With those kind of numbers I'd have expected it to be way more than '50%' over the UK.
As for the marriage laws, there's nothing really wrong with the ones we have apart from the fact that many people don't seem to feel it's
necessary these days, coupled with the fact we no-longer need to have 10 kids per family in order that some of them will survive to adulthood and that some choose other interests over raising children.
Immigration is a problem, but that's to be expected from a country that used to own half of the known world and currently is one of the top few nations in terms of its wealth and opportunity (compared to most 3rd world lands).