Evolve8eon's great idea

Just thinking it would be weird to see that some Pokémon was 'immobilized by love' when they're the same gender…

Yeah, I don't want to start a fight here. But I do want to say that it is a bit of a… I dunno how to say it, its just a bit uncomfortable for me. I also think a lot of sirens would actually attract people with a lot of different fashions… sometimes the song itself is magic, sometimes the song causes memories to resurface, and I think the most common is appearing as loved ones or similar things.

Well, I can think of something…
Depends which we go with. If its more the song that's magic, then maybe the song could be like… perhaps a sleeping effect. In greek myths, the Siren song effectively caused death (meaning Lacolin Primarina HAS GOT to have Perish Song in its moves) but for a signature move it could perhaps… low power (50 ish) but 'curse' the opponent with something… say a status condition or something else entirely. As for an ability… what if infatuated Pokemon still functioned the same, but it made it more effective? Say heightening the chances of immobilizing the opponent? That would make it kind of a tech-ish where you need that first turn to 'curse' them or infatuate if they're opposite gender, then that would get the ball rolling.