Is it a curse to have a maternal/paternal instinct?

Is it easier for the people who just lack that drive to have kids? Their lives are certainly simpler and they have more time to focus on themselves and their careers etc. I just HAD to have children, and now I have two and Im very very happy about it but it is difficult juggling career and children. I feel like I've had to make a lot of sacrifices that people w/o kids don't have to make. What do you think?