The screen that had been above Ty showing him humans mating changed to show a mirror image of him as the ray shone on him. He had never seen his body so clearly as now, and before his eyes it transformed into its opposite in response to the alien stimulation.
His figure seemed to shift inwards, his muscles becoming more petite everywhere, even on his face. His skin turned softer, his body smoothening as it became mostly devoid of hair. His figure reversed its proportions, narrow shoulders and wide hips emerging to give him feminine curves. His chest felt sensitive beyond description, his nipples widening and puffing up as flesh formed under them- these were breasts that were sprouting, he realized. Lower down, his drained penis began to shrink and his testicles were tugged up inside his body, his crotch sank inwards and split down its centre to form vaginal lips, while his penis turned into a tiny sensitive nub that settled above the slit.
In Ty's head, things were changing too. She felt herself adopt her new sex. Now she was female, and her body was made to bear offspring instead of seed. The idea of a male mounting her came into her head, and she felt juices drip from her slit in response to it. Fuck, she needed a big hard cock inside her now!