Mass paperback sci-fi: lesbian space vampires & a sub plot that involves being able to easily genetically change traits like hair/skin color, sex

I found this book on a plane in the seatback maybe in the late '90s or early '00s.

The plot involved a sort of space scavenger / corporate spy that is recruited to find someone who wants up being a space vampire that can survive on bodily fluids other than blood.

Finding the vampire involves the scavenger/spy going undercover & changing her appearance. The aestheticism that performs this for her casually drops that technology allows for people to change their sex as well. Though it's never really worked into the plot otherwise.

I think genetically modified human like that are also called Mary's Child or something like that.

It was a mass market paperback & the artwork certainly had a graphic, but sorta pre-anime influence style.