The middle grades are a crucial time for girls in making decisions about how or if they want to follow science trajectories. In this article, the authors report on how urban middle school girls enact meaningful strategies of engagement in science class in their efforts to merge their social worlds with the worlds of school science and on the unsanctioned resources and identities they take up to do so. The authors argue that such merging science practices are generative both in terms of how they develop over time and in how they impact the science learning community of practice. They discuss the implications these findings have for current policy and practice surrounding gender equity in science education. (Contains 2 tables and 1 note.)