I have a number of relatives whom I’m not sure I’m related to.

They have the right names, they sort of look like the rest of us and they all have the same memories, including the time at the family reunion when Uncle Dave and Uncle Tom got into the vicious argument about who would carve the turkey even though we were eating meat loaf.

But there’s something about some of my relatives that makes me wonder. I’m particularly concerned about my cousin Hal. He runs marathons. He bikes marathons. He rows, he jumps, he swims. He does triathlons. If there were octothlons or nonothlons, he would do them, too.

Yes, he lives in California.

He also eats flax seed, teff and whey, which I’m not sure are actual foods. I’m not even sure they are actual words.

None of this is in the family genetic structure. We are, according to our DNA, a family structured to lie comfortably on the couch watching re-runs of The Mary Tyler Moore Show while waiting for dinner to arrive. Our dinners never include flax seed.

This is a trait we have honed over time, from the earliest generations back in the old country who would lie on couches made of whey while they waited for their meat loaf, which was then, before the invention of meat, made of cheese.

The two wings of the family came together recently when we visited cousin Hal out on the West Coast. It was the morning that cousin Hal was going for a swim in San Francisco Bay. Of course, that is every morning. It’s usually right before he runs to Oregon.

This particular morning, he didn’t want to go swimming alone.

A word about the water in San Francisco Bay: It isn’t warm. In fact, it’s freezing. In fact, it’s the temperature of cousin Hal’s freezer, where he keeps his frozen whey.

Despite the water temperature, despite the fact my cousin Hal is morally opposed to aids such as wearing a wet suit or shivering, he wanted me to go with him.

I’m a good guest. I never use the last roll of toilet paper.

So I went with him.

I put wax ear plugs in my ears. I put a sleek swimming cap on my head. I put another cap on top of the cap so I could look even dorkier than usual. I swallowed a few flax seeds.

I eased slowly into the water. By the time the water got to my ankles, I knew I would never see my ankles again.

I stood motionless in the water for a long time, wondering about the chemical structure of DNA and if, just because Hal’s father and my father were brothers, does that mean we’re actually related?

Then I dove into San Francisco Bay.

Blood, you know, is thicker than whey.