Do astrology signs usually apply to twins?

I know two twins, both girls, and both born June 19th, both Gemini.

I'm a Gemini, and I've been told (and think so myself) that I fit the "stereo type" or profile pretty accurately.

I believe that the one twin completely does, more so than myself.
But her sister is like, the complete polar opposite it seems.

Just wanted to get your guys' takes on it, because I've been pondering this all day :3

 

What is more telling than the birth sign is usually the rising sign. That may, or may not, be more accurate.

 

I'm an identical twin, and you have to look at the whole natal chart.

Some twins can actually have two different rising signs!

Also, there are fixed stars and other differences between twins in a natal chart.

My sister has a stronger Jupiter and Neptune lean, her aspects are tighter there too. I have a stronger Mars and Saturn lean.