Some key points:

Comfort is often the biggest reason. Many people—regardless of gender—cross their legs simply because it’s comfortable, relieves muscle tension, or feels like a natural sitting position.
Culture and social norms matter. In many societies, girls and women have historically been taught that crossing their legs or ankles is more “proper” or “ladylike.” These learned behaviors can influence posture well into adulthood.
Context changes the meaning. Body language should never be interpreted in isolation. Crossed legs in a cold room, during a job interview, while talking with friends, or on a date can all mean different things.
Body language is not a reliable mind reader. While researchers and communication experts study nonverbal behavior, there is little scientific evidence that a single posture—such as crossing the legs—consistently reveals emotions like confidence, attraction, or defensiveness. Interpreting someone’s feelings requires considering facial expressions, tone of voice, gestures, the conversation, and the surrounding situation.
Direction and posture may provide clues, not certainty. Some body-language experts suggest that the orientation of the legs or feet can indicate where someone’s attention is focused, but these observations are probabilistic rather than definitive.

Overall, the article is best read as an introduction to common interpretations of body language rather than established psychological fact. Crossing the legs may reflect comfort, habit, modesty, cultural expectations, or personal preference, and any psychological meaning depends heavily on the individual and the context.