From Star Trek: Theurgy Wiki

The Jem'Hadar were a genetically-engineered humanoid race from the Gamma Quadrant. They served as the military arm of the Dominion and were one of the most powerful military forces in the galaxy during their time. Jem'Hadar were generated in "birthing chambers." Their growth cycle was accelerated such that they reached full maturity only three days after emergence. They did not procreate naturally, and their species consisted solely of males. Source: Memory Alpha