show Abstracthide AbstractThe National Surveys of Sexual Attitudes and Lifestyles (Natsal) are large probability-sample surveys of the British population. Together, Natsal-1 (1990-1991), Natsal-2 (1999-2001) and Natsal-3 (2010-2012) have interviewed >45,000 men and women, spanning those born through much of the 20th Century. This resource provides unique, policy-relevant evidence of the context, influences and consequences of sexual lifestyles. An advantage of repeated cross-sectional bio-behavioural surveys is that they present a contemporary picture and enable measurement of period and birth cohort effects, capturing generational changes and broad societal shifts. The most recent iterations of Natsal (Natsal-3, 2010-12; Natsal-4 2020) have collected biological specimens (swabs) from patients presenting with STIs, and these will be submitted for pathogen-specific sequence capture to generate whole bacterial genomes. These microbiological and genomic data will supplement the insights gained from linkage to routinely-collected health, administrative and geospatial datasets.