Lets see:
As far as I know there are no twins on my father's side of the family.
My maternal grandparents had nine children survive beyond babyhood. The two next to youngest were twins - boy and girl. Not at all alike. Once a new teacher in their little multi-grade rural school asked the children their ages. The girl said "Six", the boy said "Seven" (he would be seven in a few months). She never knew they were twins until the end of the year.
My aunt (second from the oldest in this family) didn't have twins, but two of her daughters did:
Older of the two had twin boys (fraternal, I think). Very different, or were they? One died an alcoholic. The other is a work-a-holic. He will probably be a millionaire. Other daughter had twins - boy, girl - very different personalities.
My uncle had twin boys (possibly identical and very much alike as children). But grew up to be quite different - maybe due to circumstances; one married and had six kids. The other married by was childless. They lived in different provinces and almost never saw each other.
So it seems that there are twins in my mother's family, but none of we four siblings were twins or had twins.
My daughter's second pregnancy had some complications. Quite likely she was originally pregnant with twins but one failed to develop, so Grandson was born a single. I often wonder what that other grandchild might have been like, and what Grandson would have been like if he had a twin. (He is seven years younger than his only sibling.)
My son lived with a girl who had an identical twin sister - almost impossible to tell apart until you knew them well. Although they lived in different cities they were very close, and, without her sister near, the one I knew was very dependent upon others and almost never spent time alone.
My daughter's man is the youngest of six kids, including his twin brother who was born just a few minutes before him. They are very different in size (the other twin has always been bigger), personality, looks, interests - and each is probably closer to one or the other of their brothers than they are to each other.