While there have never been any women playing in the NFL at the professional level, there have been several female players in the NFL at the youth level.
There is no rule in the NFL that prevents women from playing. However, the NFL is a physically demanding sport and many people believe that men have the physical advantage necessary to succeed at the highest level.
This doesn't mean women can't play football or even excel in it! There are many amazing female football players in other leagues and at all levels of the sport.
It's important to remember that everyone has the potential to succeed in sports regardless of gender.