Watch Grey's Anatomy Season 7 Episode 4 - Can't Fight Biology Online Replay: Things are hostile on all fronts when a visit to the obstetrician results in some disturbing news for Meredith and Derek, and Lexie loses it when she notices Meredith and April getting closer. Meanwhile a car crash brings in multiple traumas and Jackson tries using his physical attributes to get ahead in the operating room, while Cristina's self-doubt carries outside of the hospital and into her house hunting with Owen