Speaking Stones — Stephen Leigh

On the faraway planet Mictlan, a tiny human society has had to sruggle with severe and often disturbing complications to adapt to their desolate surroundings. There were physical mutations and birth defects among them, then an uneasy coexistence with the Miccail, an indigenous tri-gendered intelligent species. Most startling of all was the evolution of a third human sex: the Sa, or midmale.

Now the fragile peace that governs the humans and the Miccail is shattered after a young human Sa child is kidnapped, igniting all the half-buried animosities smoldering between the two groups, as savagery and violence break out across the planet. The answer may lie in an imposing carved monolith--the Speaking Stone that contains the secrets of the ancient Miccail religion. Facing annhilation at the hands of its warring civilizations, the planet's only chance for survival hinges on deciphering the stone's cryptic hierloglyphs.