This is one of the things I like most about his writing. In the scifi-whodunnit The Barbie Murders the concept of changing your body without too much trouble is used by a cult of people who all look exactly the same — lack of genitalia (i.e., 'Barbie'-like) included.

Varley wrote very much like Heinlein, but with the edgier parts of libertarianism shaved off.

Anyone looking for recommendations for reading Varley would do well to pick up some short story collections like The Persistence of Vision, The Barbie Murders, or Blue Champagne.

For a solid trilogy I can recommend the Gaea Trilogy (Titan, Wizard, and Demon), but that includes a lot of (fun!) cultural references which may be a tad harder on readers under 40.

His Eight Worlds books are great fun to read too. Pick up The Ophiuchi Hotline and see what you think to get a feel for those. These can be read independently of each other.

For young adults and anyone looking to read some scifi not quite as heavy and more reminiscent of Heinlein's juveniles, the Thunder and Lightning four book series is quite entertaining. One prescient social development he predicted there is that for an event you weren't present at to be believable (like something shown in a news broadcast or viral video) you would want a friend or a friend-of-a-friend to confirm it. If nobody was actually there, it was probably fake.