No, it's a DF is a bit messier than that, unfortunately. For whatever reason Toady still generates animal sexuality flags the same way as "civilized" flags are, so you'd either get a commitment or a romance flag for all critters (or none, but not both).
Thus what I'd like to see for animals is:
Male and no flags -> asexual male
Male and (romance or commit to male) and not (romance or commit to female) -> homo male
Male and (romance or commit to male) and (romance or commit to female) -> bi male
Male and not (romance or commit to male) and (romance or commit to female) -> hetero male
and the corresponding set for females, of course.
While in the wishing department, I'd like to see the whole set displayed for sapients, although it gets tricky:
Sex I m f M F
M - - - - - : Male icon, empty
M X - - - - : Male icon, black (adventurers only)
M - X - - - : Double male icon, light blue
M - - X - - : Male icon, light blue
M - - - X - : Double male icon, dark blue
M - - - - X : Male icon, dark blue
M - X - X - : Bi icon, light blue
M - X - - X : Bi icon, dark blue
M - - X X - : Bi icon, light green
M - - X - X : Bi icon, dark green
F - - - - - : Female icon, empty
F X - - - - : Female icon, black (adventurer only)
F - X - - - : Female icon, (light) pink
F - - X - - : Female icon, dark pink (or light red)
F - - - X - : Double female icon, (light) pink
F - - - - X : Double female icon, dark pink (or light red)
F - X - X - : Bi icon, (light) pink
F - X - - X : Bi icon, light orange
F - - X X - : Bi icon, dark pink (or light red)
F - - X - X : Bi icon, dark orange
I = indeterminate
m = romance male
f = romance female
M = marry male
F = marry female
Marriage would be indicated by darker colors, with the exception of the "odd" ones, where light means homo marriage only and dark odd colors means marriage both ways. Green is sort of a version of blue, while orange is sort of a version of pink to indicate physical gender.
This is inspired by the work Fleeting Frames did to enhance the manipulator, but DT isn't constrained to the 15 color DF palette.