The Maternifuge was an invention created by Professor Farnsworth. Zoidberg eventually made it his home. When a DNA sample is taken from a pregnant person, a number of people enter and those who aren't the other parent are ejected by being spun at high velocity, much as they would be in the machine's namesake, the centrifuge.
Interestingly, the Professor mentions that the Maternifuge rotates at a rate of 10,000 r.p.m. Estimating a radius of about 5 feet (1.5 m) from the footage, the centripetal force generated is on the order of 500 meganewtons, subjecting the characters to a crushing force approximately 650,000 the strength of Earth's gravity.