50000000

In-universe

 * Earth has become a utopia ruled by highly intelligent, beautiful women. Men are rare, fertility banquets are held, and backwards time travel has been achieved.

Speculation

 * Since most of the worlds population in this year are female, it is possible that a majority of them are, in fact, lesbians, seeing males only as a source of new genetic material
 * Although they seemed friendly and hospitable, it is possible that if Fry and Professor Farnsworth had refused to comply (and if Bender hadn't thrown the time machine further in time), they may have been forced to participate anyway, a la the Amazonians