Sisters are a funny lot. They love each other, and at the same time, they envy each other. Many sisters fall into a pattern of keeping score — with each other (for past transgressions and remuneration) and with other family members (namely you and your wife and what you've given each of them). You think that's ridiculous? Ask them what each of them got for Christmas in 1985 (assuming they were all present and accounted for at the time). While they may not list every single item, one of them will inevitably peep up and say, “Oh, that's the year she got the dollhouse she wanted and I got books.”

Oh, Great. Now You're Rich

Sometimes, your good fortune is a thorn in the side of the eldest child who feels as though she's being cheated out of a whole lot because you used to be broke, but when her sisters came along, you suddenly had money to buy them anything they wanted. You thought your financial success was good for the whole family, but apparently, you didn't take this little matter under advisement.

If one daughter has already had a modest wedding — because it was what you could afford at the time — and another daughter is planning to be married soon (now that you're referred to, in certain circulations, as a tycoon), you may be in for some resentment from the already married daughter.

Ideally, she will look at the situation rationally and say to herself, “Dad's always been as good to me as he could be. It's nobody's fault that he wasn't incredibly rich when I got married. He gave me what he could.” It's possible, though, that the voices she's hearing will be saying something more like, “He always liked Sally better. Of course she's going to have everything she wants for her wedding, when I had to cut corners everywhere.”

Before you go dismissing her claims of your playing favorites as unreasonable, try to see it from her point of view for just a minute. Is it possible that, monetary issues aside, you have favored her sister a bit? Have you always expected more from your older daughter, for example, while the younger one was given much more leeway? It's a common thing that parents do — they tend to see their younger children as babies and older children as little adults.

How does that explanation help you? What's done is done, and you can't go back and change history. Nor would it be fair to cheat your engaged daughter out of her dream wedding just because her married sister is peeved. What you can do is to be more sensitive to the issue in the future. Try to see your daughters as adults — no matter what their age or birth order — and treat them as such. Hold them to the same standards; don't baby one and play tough guy with the other. Even as adults, kids sense favoritism — and it hurts them just as badly in their twenties and thirties as it did in elementary school.

Unlucky in Love

But what if this is the first wedding in the family, and another daughter is just plain jealous of her sister's impending marriage? Or, worse, what if one sister has been through a divorce and is miserable at the prospect of seeing her sister so content with her life? A lot of dads would pretend this wasn't even happening, because then they wouldn't have to deal with it. And a lot of dads would just deal with it badly, because they would be insensitive to the jealous daughter. Fortunately, your girls got the pick of the daddy litter.

Can you really help a daughter who is struggling to accept her bad luck (whether it's real or a figment of her imagination) while being forced to watch her sister's perfect life? That depends on the daughter, and also on her situation.

A more difficult situation would find you trying to balance the emotions of your engaged daughter and her unlucky-in-love sister, who has supposedly sworn off men and who also hasn't accepted the fact that others around her aren't mourning her lost relationship. In this instance, she might really need (and, for all you know, appreciate) a heart-to-heart talk from you. She's an adult, but right now, she may need her dad to tell her that everything really is going to be all right eventually, and that no matter how badly she feels right now, it's no excuse to act badly around her sister. She isn't to blame, after all.

Will you feel as though you're settling arguments the way you did when they were truly kids? Sure. But that's your job, and you're good at it.