Keywords: mixing reaction broadcast spawning coral scaling Abstract: Coral and other marine organisms reproduce through the mechanism of broadcast spawning, where egg and sperm are released at separate locations and brought together by fluid mixing and transport. Coral fertilization is particularly important because corals are threatened by anthropogenic climate change. We idealize broadcast spawning as point sources of two reacting tracers separated by a neutral fluid. This represents a new class of problems, different from well-studied problems such as flame fronts, where two tracers fill the fluid and are separated by an interface. For the case of broadcast spawning within a vortex, we show that the vortex stirring leads to a self-similar solution with enhanced fertilization rates scaling as the Peclet number(1/3) and reduced fertilization times scaling as the Peclet number(-2/3).