The frequency of cohabiting same-sex couples tripled in the United States between 2000 and 2021, and they now account for 1.8% of households containing a couple. The same trend is observed in Australia, where they accounted for 1.4% of all couples in the 2021 census compared with 0.3% in 2001. In Spain, their prevalence increased from 0.7% in 2013 to 1.0% in 2020, and in the United Kingdom from 1.0% in 2015 to 1.4% in 2018. In France, 305,000 people were in a cohabiting same-sex couple in 2020, representing 1% of cohabiting couples in that year, up from 170,000 in 2011. The number of same-sex couples has increased more markedly for lesbian couples than for gay couples. Partners in same-sex couples are younger and more urban, on average, than those in different-sex couples