When RNA is replicated in cell-free systems, a ubiquitous problem is the hijacking of the system by short parasitic RNA sequences. In this issue of Chemistry & Biology, Bansho et al. show that compartmentalization into water-in-oil droplets can ameliorate this problem, but only if the droplets are small. This result helps to both recapitulate abiogenesis and optimize synthetic biology. Refers to: Bansho, Yohsuke, et al. "Importance of Parasite RNA Species Repression for Prolonged Translation-Coupled RNA Self-Replication." Chemistry & Biology 19.4 (2012): 478-487.