I think the groundbreaking part was Dan O’Bannon’s note in the Alien script that gave us more amazing characters in Aliens.

“At the start of Dan O’Bannon’s script for Alien, there’s a note that few other screenplays contain: “The crew is unisex and all parts are interchangeable for men or women.” It’s a line that fundamentally altered the nature of the film, affecting everything from the presentation of its characters to the way Ridley Scott and his team approached casting, and it was certainly for the best.”

source here

That seems reasonable. I think I’ll throw in my social security number and DNA sample for good measure… just in case they need it.