Sexual experimentation

As you arrive, the capsule releases you and two massive guards grab you. They lead you to a large white room holding only a chair hooked up to tubes with (oh shit) more needles. They strap you into the chair and leave you. All of a sudden all those needles push into you at once, causing you to scream as fluids push into you. You can barely hear the voice speaking to you from an intercom.

"Welcome to our lab. You will be in a blind study to document and experience human sexual relations and modifications that can be made to it. You will either be in Group A, Group B, Group C, or the control group. The fluids now entering your system will change you to fit you into your group."

The fluids finally stop pumping, and you collapse back into the chair. You don't feel anything happening to you yet, but you're sure it's just a matter of time before it does.