Who made the first dubstep song?

Actually its completely unknown who the first was. Because the genre just kind of appeared nobody knows for sure. The first place to play it, however, was FWD>> club. Founded in 2001, Forward>> was critical to the development of dubstep, providing the first venue devoted to the sound and an environment in which dubstep producers could premier new music. Around this time, Forward>> was also incubating several other strains of dark garage hybrids, so much so that in the early days of the club the coming together of these strains was referred to as the "Forward>> sound" An online flyer from around this time encapsulated the Forward>> sound as "b-lines to make your chest cavity shudder."

The early sounds of proto-dubstep originally came out of productions during 1999-2000 by producers such as Oris Jay, El-B, Steve Gurley and Zed Bias.