Even as a guy, I had always believed in the idea that guys are generally more shallow than guys when it comes to relationships. Guys are usually far more interested in sex than girls are and tend to care less about their relationships (at least in high school and college). But after spending time with lots of girls of all ages, I've come to realize that girls are just as shallow as guys. The vast majority of both girls and guys care about looks over just about everything else, no matter how much we try to deny it.
Personal experiences have affirmed the idea that girls are shallow too. Back when I was a freshman in high school, I met a really pretty girl in my class and I'd started talking to her because she sat next to me. Let's call her Jordan. She was had a cute face with long brown hair, she was smart, and she played volleyball. Just like me, she was a single freshman at the time. Back then, I didn't take care of myself as well as I do now. I had messy black hair, a 5 o'clock shadow, and my teeth weren't perfectly straight (they weren't that bad though). Although Jordan didn't seem too interested in me, we still talked almost every day for the first few weeks of the year. Over the weeks, she started acting distant towards me, and I took the hint and stopped initiating conversations with her. It continued like that for the rest of the year into summer vacation. The year after, my sophomore year, I started working on my appearance and bettering myself. I started using hair gel every day, wearing Invisalign to straighten my teeth, wearing nicer clothes, and making sure my face was shaved. She started dating a an older senior that year, and she seemed pretty happy with him. About halfway through my sophomore year, she started to talk to me more, smile at me, and always ask for my help. When I would sit next to her, she would move her chair closer to me, touch my arm, laugh at all my jokes, etc. She never did anything like this the year before when she was actually single, and when she started showing these signs, she had recently gotten a boyfriend. Keep in mind that nothing about me had changed except for my external appearance. The logical conclusion from all of this is that her opinion towards me changed only because I had become more physically attractive.
Beyond my personal experiences, there are plenty of examples of both girls and guys being exceptionally shallow. Some girls are so obsessed with their appearance that they'll spend hours getting ready or won't even let someone crack a window in a car, despite the fact that their boyfriends tell them they look beautiful and that they don't need to work so hard. Othere will only date guys with lots of money, expecting them to constantly buy gifts and give financial support. Then there are guys, many of whom high five another guy for having sex with a girl, but make fun of him if he says he actually wants a relationship. Guys are just as guilty of the aforementioned behavior of only paying attention to girls when they are physically appealing. There is much more to a person than their appearance, popularity, or wealth.
To make it clear, this is not to say that everyone behaves this way. Plenty of guys and girls alike look past the superficial qualities of people and care deeply about a person's compassion, intelligence, loyalty, and trustworthiness. I consider myself to be one of those people because I could never imagine myself in a relationship with someone who has an ugly personality. Again, it's perfectly fine to want a potential boyfriend/girlfriend to be attractive, but people have to look at the entirety of a person before making a positive or negative judgment about him or her. It's a lot easier to be happy when you're in a relationship with a person who is beautiful on the inside and on the outside.