Masculinity and femininity are portrayed quite differently in Romeo and Juliet by William Shakespeare, as gender roles were very distinct in his period.
The first difference in gender roles is that physical violence, in the form of fighting, rioting, and dueling, is portrayed as the exclusive dominion of males in the play. The only physically violent act committed in the play by a woman is Juliet's suicide, and that is violence towards herself not towards others.
Next, raising children is the task of women, whether mothers in the lower classes or hired nurses in the upper classes. Thus the Nurse functions as a mother figure in the play and Juliet's father is a distant authority figure.
Taking initiative in relationships is also a distinctively masculine role; while Juliet can accept or reject Romeo's advances, she couldn't just walk up to a man and ask him to dance at a ball.
Finally, the priesthood, and thus religious authority, in the play is exclusively masculine. Only a male priest could marry the young lovers.