This article is concerned with the impact of recent reforms to specifications for science exams taken by secondary school students in England at age 16+, and other policy shifts, particularly that towards "triple science". It draws on data from the National Pupil Database/Pupil Level Annual School Census, together with fieldwork in a range of schools. These data suggest that the increasing diversity of provision at key stage 4 (ages 14-16) may be leading to increasingly stratified student take-up, particularly according to attainment, and that schools and teachers themselves differ in their judgement of, and responses to, the new forms of provision. The resulting issues of equity and access are discussed. (Contains 5 figures and 2 tables.)