In the movie, an astronaut gets himself lost on some planet by accident and his shuttle goes back to Earth. On it, he meets a female alien. He impregnates her and they have a baby. It was from the 1990s.
Could this be a misremembered description of Enemy Mine?
In the late 21st century, an interstellar war between the humans (associated as the Bilateral Terran Alliance, or BTA) and the Dracs (a sentient, bipedal reptilian humanoid race) is fought. Battles are periodically fought between fighter spacecraft, and no human pilot hates the Dracs more than Willis E. Davidge (Dennis Quaid). During one such battle, Davidge and Drac pilot Jeriba Shigan (Louis Gossett, Jr.) engage in a dogfight which results in both crash-landing on Fyrine IV, an alien world uninhabited by intelligent life, with two moons, a breathable atmosphere, water, native fauna, and a hostile environment.
After initial hostilities, the two eventually learn to cooperate to survive. They work together to build a shelter for protection against meteorite storms, a natural phenomenon that periodically strikes the planet. Over the next three years, they overcome their differences, become friends and learn each other's languages and cultures. Each saves the other's life several times.
The alien isn't female but does have a child that the human ends up as a surrogate parent to.
Dracs are hermaphroditic and reproduce asexually.