One of the few things older than the battle of the sexes is the origin of the sexes. How sexes evolved in the first place has been a lasting mystery in biology. Thanks to some transgender algae, scientists may have cracked this evolutionary whodunit.
A simple trick of genetic engineering forced female Volvox carteri algae to produce sperm and males to produce eggs. The process revealed that the evolution of males and females was much more straightforward than anyone thought.