Interest in anal intercourse has also come from research in human immunodeficiency virus (HIV) transmission. Several studies have quantified the increased threat of heterosexual transmission from one particular act of anal intercourse as compared with 1 act of vaginal intercourse (Boily et al., 2009; Leynaert, Downs, & de Vincenzi, https://vbefi.jiliblog.com/79768415/can-same-sex-couples-get-ivf-on-nhs-no-further-a-mystery