I'm very close to my identical twin who came 4 minutes before me. Here's the whole family:

* Eldest sister: 6 years before me
* Older brother (twin): 4 minutes before me
* Me
* Younger sister: 3 1/2 years after me.

My wife is very close to her brother, who is very closely spaced to her:

* Bee
* Younger brother: 14 months younger than her

I'm curious if people are closer to their closely-spaced siblings, or to the siblings who are spaced farther apart!