Turning Point: Harmony, the world’s first A.I.-powered sex robot, began shipping to consumers this year.

I often imagine a future in which sex doesn’t exist. Many people seem to think this is weird, but for me it’s a world that feels wonderfully nostalgic.

When I was still a child, before I came across the word “sex” (which in Japanese is written in the jagged katakana script, and often indicates sexual intercourse between different sexes), the concept didn’t exist in my world. Every day I was amazed by my own body. When I was about 3, I remember exploring inside myself. When I explored certain places, the water inside me felt like it had turned into soda and fizzed, and then abruptly evaporated from all over me. This had a profound impact on me. I called my strange and wonderful discovery “eppi,” a made-up word that sounded cute and mysterious to me. It had an electronic ring to it that I thought somehow suited the feeling.

When I started elementary school, there was a column in a manga magazine soliciting letters about readers’ inventions. I wondered whether I should write in about my “eppi” invention, but then I reconsidered — maybe I shouldn’t let grown-ups know about this incredible discovery that existed in my body (and maybe in everybody, although so far I had tested it only on myself) just yet. It probably wouldn’t occur to anyone even in their wildest dreams that the water in their bodies could turn to soda, so I didn’t think anyone would believe me. When I grew up I could be a researcher and let the whole world know about this amazing discovery, I thought.