For a significant portion of the film the boy appears nude. Since he has been alone his whole life on this planet he has no idea of modesty. The young actor is very convincing and makes no effort to hide himself in front of the camera. He is seen fully and extensively both from the rear and the front.
Part way through the film one of the crew members gives him a shirt. For the remainder of the film this is his only covering. By the end of the film, though, this shirt is so ripped and torn that he is once again basically nude, and nothing is hidden.
An eleven-year-old boy spends most of the film completely nude. Having been raised by aliens on a desert planet, he is not accustomed to wearing clothes. Upon discovering a human spacecraft on his planet, he wanders onboard and mingles amongst the crew, both male and female, still fully naked, exposing his bare bottom and genitals to them and us at various times throughout the film.