Hence, Throbbing Gristle was seminal because it spawned Psychic TV, Coil, Chris+Cosey. Bauhaus was seminal because is spawned Love and Rockets, Tones on Tail, and Peter Murphy's solo work.
The Wikipedia entry for The KLF lists them as a "seminal band of the British acid house movement." In that case, I think they are using seminal to suggest that the act helped spawn the entire genre. While that usage is not incorrect, it's just not how I've typically seen it used. (I left a note to this effect on the discussion page for people who clearly care more than I do, such as Kingboyk.) Unless, in addition to The Orb, all the other names under which the KLF released recordings count as separate acts.
I just thought I'd check with y'all, since some of you have written your share of music reviews, to see what you mean when you refer to a music group as seminal. And if your interpretation matches mine, how many bands does the originator need to spawn before it merits the seminal designation?