1. If a couple are raising a kid, they have moral responsibilities for their kid’s desires. For example, if the kid wants to go to school to study, they must send him to school because it’s kid’s right to have education. Therefore, people have the obligation for people’s desire.
2. If is true that people don’t know what the people in future will be like, so people don’t have obligations for them. However, as far as I am concerned, people have the obligations for people in future is not based on what future people’s desires are but based on present people’s expectations. For example, the couple work hard to make more money because they want their kid to have better education. They have a high expectation for their kid. Therefore, they don’t have to know what people in future’s desires. They still have obligations because their desires for people in the future.