It's generally accepted knowledge that "typical male behavior" is to place more emphasis on looks and to think more in terms of sexuality. We certainly do see Romeo exhibiting both of those characteristics. However, one thing that is not necessarily typical male behavior is to become as easily emotional and brokenhearted as Romeo does.
There are several instances in which we see Romeo placing great value in a woman's looks. One instance occurs in the very first scene in which we meet him. We learn he has been moping about because he feels brokenhearted over Rosaline's rejection. Romeo tries to keep secret about why he is feeling so blue and who has broken his heart, but when his cousin Benvolio asks who she is, the first thing Romeo tells him is that "she's fair," meaning beautiful. His fixation on Rosaline's beauty shows us that, typical of male behavior, he has fallen in love with only Rosaline's beauty.
We see him act in the very same way when he meets Juliet. The very first thing he notices about Juliet is her beauty, which he praises by first saying that "she doth teach the torches to burn bright," meaning that she shines even more brightly than the torches being used as lamps, thereby teaching them to actually burn brightly (I.iv.46). He even refers to her beauty as "[b]eauty too rich for use, for earth too dear!" (49). These comments among many others shows us just how much Romeo is fixated on physical appearances. Not only that, typical of male behavior, he proves to be very fickle. It takes him no time at all to switch from loving Rosaline to loving Juliet, all due to physical attraction.
However, what is not typical of male behavior is Romeo's irrationality. It is irrational for him to pine away, night after night, over Rosaline the way that he does. As his father explains to Benvolio, Romeo has been staying out all night long lately and been seen in a certain part of town, presumably Rosaline's part of town, standing under a grove of trees, "with tears augmenting the fresh morning's dew," meaning crying (I.i.128). Romeo's response to love's rejection is unhealthy and not typical of male behavior.