Ida Davis (formerly Daniel "Dan" Quagmire) is Glenn Quagmire's mother from Family Guy. She is transgender and has undergone sex reassignment surgery. She is voiced by Seth MacFarlane.
Background
Ida is a U.S. Army war veteran who fought in Vietnam, serving as a war pilot. When she wasn't fighting, she engaged in sexual activity with fellow soldiers. During this time, she came to grips with the fact that she was actually transgender.
It wasn't until the events of the episode "Quagmire's Mom" that she told her son, Glenn, about this. It was not easy for him to adjust to this, because it was in the Quagmire family name for the men to act like ladies' men, so this was kind of embarrassing to him. However, Quagmire came around to support his mother, and was happy for Ida to continue with her transition.