When I told friends in California I was flying to the East Coast for a family wedding, I stumbled over how to explain my relationship to Jennifer, the bride.

To some I explained: "She's my ex-husband's daughter by his second wife." To others, perhaps to be provocative and draw attention to the lack of kinship terms, I said, "She's my daughters' sister."

Of course, technically she's my daughters' half-sister, but many years ago my daughters told me firmly that that term "half-sister" was utterly ridiculous. Jennifer wasn't a half anything, she was their real sister.

Some of my friends thought it strange that I would be invited; others thought it even stranger that I would travel cross-country to attend.

The wedding reception brought an awkward moment or two, when some of the groom's guests asked a common question, "How was I related to the bride?" With some guilt at violating my daughters' dictum, but not knowing how else to identify our kinship, I answered, "She is my daughters' half-sister."

A puzzled look. It seemed strange to them that I was a wedding guest.

At several points during this celebratory day, I happened to be standing next to the bride's mother when someone from the groom's side asked us how we were related. She or I pleasantly answered, "We used to be married to the same man." This response turned out to be a showstopper. The question asker was at a loss to respond. First and second wives aren't supposed to be amicable or even respectful toward one another. And certainly, first wives are not supposed to be included in their ex-husband's new families. And last of all, first and second wives shouldn't be willing to comfortably share the information of having a husband in common.