I'm not sure if there is any veracity to the "NJ girls aren't beautiful" claim, or what would even cause this to be true. Certainly everyone has different standards of beauty, but I'm not sure what would make one state more beautiful than another.
It's not like this is Europe where different countries have centuries of partial isolation to develop different genetic traits. I could understand if someone said Irish girls are prettier than Greek girls, or vice versa. But in the US, you really don't have the same types of genetic differences from state to state.
You can't even point to a predominance of one ethnicity to support a claim of genetic differences. NJ is a real hodgepodge of ethnicities. The largest national ethnic group in NJ is Italian. But only about 14% of New Jerseyans claim any Italian heritage.
I can't think of any genetic reason that girls in NJ should be more or less attractive than girls in any other state.
Maybe lifestyle impacts the perception of beauty. For example, being fat is usually considered unattractive. Plus being obese is corrolated with other unhealthy lifestyle factors. But NJ has one of the lowest obesity rates of any state. And for childhood obesity for ages 12-17 (which certainly is most relevant for those about to enter college), only Oregon has lower childhood obesity rates than NJ. So based on lifestyles that don't result in obesity, you would expect NJ to have among the most attractive people.
Other factors seem to favor NJ as well. High levels of affluence which are correlated with better health, better dental care, better grooming, and better clothes (plus NJ is intricately connected with New York City, which is a global fashion capital, which adds to the fashion sense seen in NJ).
I could understand if someone only claimed that the Los Angeles area had a high proportion of attractive women, and attributed that to attractive people moving to the LA area for opportunities in the Film/TV industry, where physical appearance is important. But that doesn't apply to other areas of California, and certainly not to other states. And certainly that is countered by people moving to the NY area for opportunities in the stage and fashion industries, where physical appearance is also important.
So I can't think of any reason to think that women in NJ are less attractive than other states, and unless you like fat people I would suggest that women in NJ are actually more attractive.
However, I will note that women in warmer climates are more likely to wear skimpier clothing, and women in colder climates are more likely to be covered up, especially in winter months. So if you falsely think "there's a girl showing a lot of skin" is the same as "there's a pretty girl", then you'd falsely think girls in warmer climates are prettier.
