In this era where the technology is underdeveloped or still developing, Luis is not expecting to see an over-the-counter pregnancy test kit. In fact, he is more than curious to know what kind of surprise the moon elves could give him. Are they going to check his pulse like in Eastern medicine? Or will they ask him to pee on wheat and barley seeds and see if they grow? Ancient people from Earth believed that if pee sprouts marinated any of those seeds, then it meant that the woman was pregnant. The same way was used to determine the sex of the fetus.
If the barley grows, it means a male child. If the wheat grows, it means a female child.
It is pretty fascinating to learn those bizarre beliefs. Luis is excited to learn from his people. And at the same time, he wants to know the truth. He can't keep on second-guessing his condition because that is just plain negligence on his part.