In Angels in America, how does Tony Kushner challenge the traditional understandings of gender?

Tony Kushner challenges traditional understandings of gender in his play Angels in America by casting the same actors in multiple major and minor roles. The most common staging is to cast eight main roles and divide all the minor ones between those same people, crossing male and female actors with male and female roles. This doubling or tripling of roles and the crossing of genders is required by Kushner in his script. In this way, audiences are encouraged to focus on the role rather than the gender of the actor or the character. That implies an implicit acceptance of gender fluidity.
The play itself is also a challenge to traditional understandings of gender. It documents the lives and loves of gay men in New York in the 1980s, presenting couples with joys, problems, hopes, and fears that any couple, same-sex or not, would recognize. This forces the audience to superimpose the lives of the couples they see on stage on the lives of themselves or other couples (the implication here is heterosexual ones) they know and to confront notions of the fluidity of sexuality and gender.