Sex allocation is an organism’s decision on how much of its reproductive investment should be distributed to male and female functions and/or offspring. Under most conditions, the optimal ratio is 50:50, but that can change under certain circumstances. Sex allocation determines what sexes sequential hermaphrodites should be at each part of their life as well as how simultaneous hermaphrodites should behave. Some species have more control over the sexes of their offspring than others, and adjust the sex ratios of their offspring depending on the environment and conditions.