Delaware Senator Tom Carper (D) on Monday became the 51st cosponsor of the Employment Non-Discrimination Act, according to the Huffington Post.

"Senator Carper believes it is important for federal law to explicitly prohibit workplace discrimination on the basis of sexual orientation -- in the same way that current law addresses race, sex or religion -- in order to ensure that all Americans are protected equally under the law," Carper spokesman Ian Sams told the Huffington Post.

The legislation, which first emerged in 1994, would expand federal anti-workplace discrimination laws by making it illegal for employers to treat their employees differently based on their sexual orientation or gender identity. Federal law currently provides similar workplace protections regarding race, religion, gender, national origin, age and disability.

Though ENDA is supported almost entirely by Democrats, two Republican senators -- Susan Collins (ME) and Mark Kirk (IL) -- have also signed on as cosponsors.

Research has uncovered that LGBT job applicants faced significantly less discrimination in cities that had adopted legal protections for LGBT workers than cities that had not.