What can parents do to keep from having favorites among their children?
Let me just give a reality check here, first: every parent has seasons when one child is behaving better than another child. And you like children to behave! And therefore you like what this child is doing better than the other ones.
These kids are going through phases, one after the other. They're up and down and all over the place. So if "favorites" means you like the way one is behaving better than the others, that's going to be true at any given time. You might as well be honest about it. Then the question becomes, "How do you avoid letting that become an abiding strong preference with preferential treatment and preferential care and preferential praise?" Those are the issues.
1) The first answer is to know that God, in relating to his family, loves his children and loves them all. You are loved by God, though you don't deserve to be loved.
In other words, let the gospel have its deep effect on you as a person in God's family to make you feel stunned that you're even in the family. So be glad that God has been gracious to you so that you come to all your children then with a gracious disposition.
This is what, I think, is the biggest issue for parents: are they coming toward their children with grace that the children can perceive and that isn't conditioned primarily upon performance and behavior? Do they discern in and through their good and bad behavior, "Mommy and daddy love me, they're there for me, they're on my side"? Or is it constantly communicated to them that mommy and daddy's love really rises and falls entirely with the child's behavior?
So that's the first thing: get a good gospel foundation of grace so that as you look at your children, the fact that one is in a messy phase right now does not mean that you don't love him. In fact, I would guess that there have been phases where one of my boys is so displeasing to me that he is getting all of the attention. And the others feel, "He must be the favorite!" Well, he's not the favorite at this point. He's just the neediest. So it is very very complicated.
2) The second thing I would say is to labor to be pro-active in the way you love your kids, not just reactive. That might be almost the same thing as what I just said, but it might make it a little clearer.
If you're only reactive—you're doing things for them and saying things to them as reactions to what they just did or said—there is inevitably going to be an appearance of favoritism. That's because the good little kid over here (usually the firstborn) is not going to get any negative attention, whereas the second, third, or fourth will get a bit more, and the feeling is "favorite." And that's all rooted in, as a parent, just reacting all the time.
So you need a positive sense of, "I will pro-actively come toward my children with wisdom, with grace, with guidance, with love, and with benefits before and independent of—to a degree—their way of talking or acting."
3) The third thing that comes to mind is just to be aware of the problem. The person asking this question is way down the line in answering the question by simply being aware that it is a problem, and thinking through why it is a problem to play favorites with your children.
What a parent wants to do is not say, "Your behavior doesn't matter." It does matter. "You're going to get a spanking if you do this." Or, "You're going to get some time out." Or, "You're not going to take the car this weekend. There are consequences." And yet you want to have an over-arching communication to each of your children that every one of them is precious to you.
I wanted my sons—now I've got a daughter coming along, but I'll just say this since the boys are all up and out of the house—I wanted them growing up to say, "Daddy is really glad I'm in this family. And daddy is always there for me."
I'll give a little tip here: when the boys reached twelve, we had this special outing. We'd go to Pizza Hut (or some nicer restaurant since Pizza Hut was the date place). And I had a little speech planned—you know, about the birds and the bees, and about being a boy and about sexuality and girls and dating and whatever—and I would say to them, "OK. Freedom is coming, and I can't control you. You going to be on your own. I just want you to know that I am totally there for you anytime, anywhere. If you go with some guys to a party after a ball game, and it turns out to be totally what you didn't expect—like sex and drinking, etc—and you rode with somebody else but don't want to be there, I will walk on glass to come get you. And you don't have to say a word. Just pick up the phone and say, 'I'm at such and such a place, and I'd like out of here,' and I'm there, no questions asked."
A dad who says that to every son, despite all the diversity between them, creates one common sense among them: "He is there for us, and we can count on him."