Advances in CS appropriate for CS1 and CS2 made by female computer scientists
I think Rear Admiral Grace Hopper is perhaps the easiest to explain to new students, and to tie in with an important advancement in computer science.

I try to discuss the transition from early programming in machine language to programming in higher level languages. I'll usually show the students some machine code that I will tediously decrypt. Then I show and talk about assembly languages. Then I'll make a point that "there has to be a better way". Then I'll introduce Grace Hopper and her ideas about compiled languages. Showing a little COBOL code with English words and contrasting it to the equivalent machine code is striking.