Almost immediately, Eric felt a very warm sensation in his crotch. It started at the tip of his penis and then spread down into his scrotum. It warmed up and tingled, and then the feeling started to subside. It faded gradually until he felt nothing down there. Absolutely nothing.
His body felt different, but he couldn't place exactly how. His pants fit more loosely in the front, and there was a very slight warmth across many parts of his skin.
Then came the sudden urge to urinate. It was like his bladder was filling rapidly. He started squirming around and said, "I have to go to the bathroom. NOW."
"Go on," said the nurse. "Come back as soon as you can." She quickly jotted some words in a log.
Eric ran to the restroom, opened his pants, and screamed.
His outer genitals were gone and in their place was a tiny slit where the base of his penis would have been. If he could see inside his crotch, he would have seen that his internal sex organs were also gone (prostate, etc). He could see many hairs in his underwear where he had shed all his pubic hair.
He was no longer male, but he didn't have female organs either. He just had one tiny slit and it was for urination, as he swiftly found out. He could no longer restrain the urge, and the slit opened, spilling forth a spray of urine. He peed for what seemed a very long time, and then the spray reduced to a trickle down the front of his crotch. His bladder now empty, he wiped himself clean with some toilet paper. He brushed a hand over his crotch, mind reeling over what was no longer there. He pulled his pants up again and rushed to the mirror looking for anymore changes.
It seems that some secondary sex characteristics were also affected, especially facial hair. He'd had a five o'clock shadow when he came to the experiment, but his face was now completely smooth. He looked down his shirt and noticed that he had also shed what chest hair he had.
Eric stood perplexed for several moments and then hurried out of the room.