Same-Sex Marriage Question

Churches that Sanction same-sex marriage: Presbyterian, Conservative and Reformed Jewish Movement, Quackers, Unitarian, UCC and Evangelical Lutheran Church
Churches that prohibit same-sex marriages: American Baptists, Mormons, Lutheran Missouri Synod, Orthodox Jewish, Catholic, Southern Baptist, Methodist and Assembly of God.
No clear stand: Buddhism and Hinduism

Views by Generations: Supporters of same-sex marriages:
Millennials (1981 or later) 67%
Generation X (1965 - 1980) 46%
Boby Boomers (1946 - 1964) 53%
Silent Generation (1928 - 1945) 35%

My question: Why do you think there is an increase in support of same-sex marriage?