Few things demonstrate the importance of population aging as clearly as the shift in policies and opinions concerning same-sex relationships. Although same-sex sexual conduct was decriminalized in the Sexual Offences Act 1967, twenty years later, in section 28 of the Local Government Act of 1988, local authorities were prohibited from ‘intentionally promot[ing] homosexuality or or pubilish[ing] material’ with the intent to do so. A further twenty years on, in the Civil Partnership Act 2004 the Labour government introduced same-sex civil partnerships for same-sex couples, which were legally equivalent to marriage. Employees of local authorities were required to sanction them. Finally, in 2014 it became possible for same-sex couples to marry. This rapid change, which took place in less than fifty years, means that older people have had to adapt relatively quickly to a fundamental social change. This talk will discuss some of the research that underlies Scot Peterson’s and Iain McLean’s book, Legally Married: Love and Law in the UK and the US, including the historical development of marriage law and the rapid acceptance of same-sex marriage.