Kha'Zix - Male
Rengar - Male
Hecarim - Male
Ziggs - Male
Fizz - Male
Xerath - Male
Skarner - Male
Yorick - Male
Warwick - Male
Teemo - Male
Alistar - Male (It's a cow... So don't get up all on the masculine chest)
Heimerdinger - Male
Amumu - Male
Fiddlesticks - Male
Jax - Male
Karthus - Male
Kog'Maw - Male
Malphite - Male
Maokai - Male
Mordekaiser - Male
Nasus - Male
Renekton - Male
Nautilus - Male
Nocturne - Male
Rammus - Male
Rumble - Male
Kassadin - Male
Shaco - Male
Trundle - Male
Twitch - Male
Urgot - Male
Veigar - Male
Yorick - Male

Anivia - Female - Very pretty, not ugly at all

Blitzcrank - Neither
Cho'Gath - Neither

.... Where are all the female champs?

it is a battle field after all. It should be expected to see more male fighters...

You want more animal like female champions. Very random. Go to the player concepts forum and draw up a sketch.

A lot of the ones you listed do not have ambiguous appearances.
Just as examples. Kassadin, Warwick, Rengar and Nasus. What part of them says "ambiguous"?

What do you even mean by "ambiguous"? Because from your list, anything that isn't completely human and doesn't have boobs look ambiguous.

So you're just asking for more flat chested non-humans. Really? Who cares, other than you.
Dumb.

Btw, Tristnana and Poppy.

Like RamboRal said, many of the champs you listed dont seem ambiguous at all, many of them seem rather obvious to me.

Its pretty simple as we are dealing with Riot here. If it doesnt have boobs, its male.

EDIT: Cho'Gath would be male but then Riot would have to censor his massive shlong at six Feast stacks.

You keep using that word. I do not think it means what you think it means.

am·big·u·ous/amˈbigyo͞oəs/

Adjective:

(of language) Open to more than one interpretation; having a double meaning.

Unclear or inexact because a choice between alternatives has not been made.

You basically just listed a bunch of humanoid type champs that aren't quite human or are anthromorphic. Nothing ambiguous there.

Boobs sell this is a time tested and proven theory.