I don't have a ton of knowledge about astrology and most of the time I'm sure I don't even believe in it. But for some reason, even though birthdays rarely come up in the text, I do try to choose signs for my characters to keep them at least partially consistent with their dominant traits. I guess that's a backward way to do it, huh? Instead of that their traits depend on their birthdays, I make it so that their birthdays depend on their traits. That's the advantage to being the creator here. After over a year with these characters, I never did settle on specific birthdays for any of them. I had a vague feeling that Jared's a Scorpio, Mikey's a Capricorn, Daniel and Kendall are Leos, Rosetta's a Virgo, and Seth's a Pisces. That is as far as it got and none of those were set in stone.
But yesterday I was pondering a potential exchange that would require two characters (Seth and Rosetta) to discuss their birthdays. So, I chose birthdays (February 28th and August 28th) and took a quick look at some information about Pisces and Virgo for curiosity's sake. They way I've been writing them is pretty spot-on with what you would expect of people of those signs (especially Rosetta), which was a surprise on its own. Then I learned that they are opposite signs on the zodiac. One of the big themes of this story is about how different these two characters are from each other. I didn't plan their signs to be opposite though. I mean, I wasn't like, "Hmmm. Which signs can I choose to illustrate my point?"
It just happened like that! Pretty cool.