Nothing makes a mother happier than to know her grown children are hanging out together, chatting in the evenings after work, caring. That’s the way I feel, and I remember Mom feeling that way, too. What’s amazing is how the practice carries on through time, even when the parents are gone.

My brothers and sister and I spend holidays together when we can, check up on each other, chat in the evenings after work. And we care. The caring is not without a price, but it’s always worth it.

My parents gave us many gifts — optimism, resilience, a love of ideas — but best of all was the gift of each other, a fact we would have found shocking as squabbling kids in the back of a hot station wagon.

I write this today because it’s Ellen’s birthday, as good a day as any to say how lucky I am to have a sister, how I can’t imagine going through life without one.

(Ellen and I have given each of our daughters two sisters!)