Leonard and Sheldon had a female friend/colleague in the show’s unaired original pilot.
Her name was Gilda, played by Iris Bahr.
The Big Bang Theory Wiki page claims Gilda was “much” like the subsequent Leslie Winkle, played by Sara Gilbert.
Still, their differences were significant.
Whereas Leslie’s presence was often competitive .and difficult, filled with the awkward sexual tension emanating from her “between the sheets” relationship with Leonard, Gilda was a more easily accepted third member of the trio.
Gilda fascinated about a long-term relationship with Leonard, thinking about marriage and children, Leslie’s interest in Leonard was far more carnal and short-term.
Then there was the girl’s interest in Sheldon. Leslie never passed on a chance, however small, to belittle her fellow scientist. Her disdain for him was considerable.
As far as Gilda was concerned, she and Sheldon were far more simpatico, so much so that (commence jaw-dropping in 3-2-1…) they “hooked up” on the sacred grounds of a Star Trek Fan Convention (Most bazinga indeed).
Of course, the final version of Sheldon is about as virginal as one gets.
No official word on why Gilda never made it to the final version of the sitcom.
In addition to her acting talents, Iris Bahr is also a writer and director. She is a graduate of Brown University where she majored in neuropsychology and religious studies.
She will be seen in the upcoming HBO comedy series, The Brink. It is slated to premiere in the summer of 2015.