Funny how it's only when you switch genres that you learn how involved those other genres are, isn't it? I ran into that in the last year, switching from fantasy to westerns. I thought everyone knew what a western was, simple enough, right? NO! It's got all its own conventions, the well-known ones, and a whole lot of others that no one realizes are there until you start outlining exactly what you are trying to do. Needless to say, I feel like little more than a baby even after a year of working on it.
SF and Romance? Possibly not the easiest task, but certainly not impossible. It would make for an interesting read. SF has a reputation of being rather unemotional, and even authors that delve into psychology rather than the hard sciences aren't quite fully accepted, though some of the best work in the field has been in this area.
And if I may make a (possible useless
) recommendation, try and intertwine your romance and your plot as absolutely tightly as possible, like making a couple at odds with each other over some scientific problem, both proposing good solutions to a big problem, and make them rivals, which would pull them together and apart at the same time, nice and angsty. Or have two characters that want to get together, but they are closely related (family or co-workers) to a couple (of scientists) in the middle of a divorce, and the divorce is interrupting the pursuit of a needful goal, interrupting, corrupting real scientific pursuit as they argue over their vast estate...