Electronic Music should be seen more as a means of creating music, rather than a style.
Electronic Music includes any type of music that was fabricated using electronic instruments as opposed to acoustic instruments. Such instruments could include: electric guitars, synthesizers, computers, turntables, samplers, theremins, etc..
An electronic musician could include anyone who uses the above mentioned electronic devices to compose, arrange, and produce music.
An early pioneer of electronic music might be Raymond Scott. Raymond experimented with the earliest forms of sound synthesis and utilized them in the production of music, sound effects, and other inovative things. He might be best known for his Soothing Sounds For Baby series and for scoring movies and cartoons. But that's another write-up altogether.
Any musical genre could technically be made via electronic means. Bela Fleck and the Flecktones, for instance, use electronic instruments in their Jazz/Bluegrass/Funk/Pop recordings. Yanni uses these instruments in his Adult Contemporary recordings. Limp Bizkit uses turntables in whatever it is they do. And Mannheim Steamroller use electronic instruments in their Classical recordings.
I feel people often make the mistake of considering electronic music to be a genre. Man, that really irks me! I mean! Damn. It's just silly!