'An Old Flame With a New Wick' - Season 1, Episode 18
Charlie is stunned to learn his ex-girlfriend is now a man... and dating his mom.
Air Date: February 29th 2004.
Charlie: I got a little e-mail this morning from an old girlfriend who says she needs to "see me."
Berta: No kidding? I wonder if she's "knocked up."
Charlie: Nobody's knocked up. I haven't heard from her in four years.
Berta: So she's bringing you a three-year-old.
Alan: (to Charlie about Evelyn dating Bill, who used to be a woman) One of us has to tell her.
Berta: I'll clean your house free for an entire month if you let me do it!