star trek the next generation: has holodecks, which are enclosed rooms in which objects and people are simulated by a combination of matter, beams and fields onto which holographic images are projected, making them appear real and solid to the touch. This allows for the simulation of any combination of people and locations that look and act real. Holodecks are used for exercise, training simulations, and reconstructing environments from classic literature.
star trek deep space nine: holodecks are for fucking
star trek voyager: holodecks are definitely for fucking, including but not limited to fuck with or die, captain’s discretion with lord byron and captain prerogative with scruffy turn-of-the-20th-century Irish bartenders
star trek enterprise: we don’t have holodecks but we learned from other races that do that they are indeed for fucking, and occasionally mpreg.