I became interested in what makes for a good mother-in-law/daughter-in-law relationship shortly after I got married. Being a sociology professor, I decided to investigate the relationship and see how other families handled the situation. I interviewed over 200 mothers-in-law, daughters-in-law, sons and fathers-in-law. Here is the advice they gave:

Advice for daughters-in-law:

1. Remember that your mother-in-law is always going to be your husband's mother.

It may be frustrating sometimes to see the way that your mother-in-law is offering your husband unsolicited advice or treating him as being younger than he is. Remember, though, that she is still his mother and that she always will be. It is hard to automatically turn off being a mother. There may be many things that she would like to do that she does not, and you don't even know about them. You will be better able to handle the situation when you put her behavior into this context.

2. Include your mother-in-law whenever you can.

In-laws often feel that they are on the outside of their children's lives looking into them - especially the mothers of sons. Your mother-in-law will feel more secure with your place in her son's life if you can include her wherever possible. She will appreciate your willingness to involve her and be more likely to reach out to you if you include her in your family as well.

3. Give your mother-in-law some time alone with your husband.

Your husband's time may be scarce and you would like it for yourself and your children. Chances are, though, that you still get more of his time than his mother does, as it should be. Try to share when you can. Giving your mother-in-law some time alone with her son may be one of the best gifts she ever received.

Advice for mothers-In-law:

1. Stand back and let your son have his own family.

The thing that your daughter-in-law wants more than anything is the opportunity to have her own family. She cannot do that if you keep your son tightly attached to you. Give them the space to have their own family. Let them establish their own holiday traditions, raise their children the way that they see fit, and manage their own decisions. You will find that your son will be more likely to come around under these conditions, and that you will gain a daughter as well.

2. Let your daughter - in-law make her own mistakes.

So she makes some mistakes. You probably did when you were first married, too. She will learn though, and she will love you all the more if you do not point them out to her.

3. Respect the fact that your daughter-in-law is the mother of your grandchildren.

It may be more than tempting to say something when you believe what is best for your own grandchildren is at stake because you do not agree with your daughter-in-law's actions. But respect the fact that she is their mother, and she is the one who is responsible for them. You may have to leave the room sometimes in order to keep your thoughts to yourself, but it is usually for the best in the long run.

Advice for sons:

1. You may need to step in when your wife and mother are at odds

No one wants to get involved in someone else's conflict, but your wife needs your support. If your mother and wife are not getting along, you will need to step in and say something to one or both of them. Your mother will listen to you more than she will listen to your wife. Help your wife in making the transition to being a part of your family.

Advice for fathers-in-law:

1. Support your wife in her effort to let go of your son.

You may occasionally need to remind your wife of her need to let your son be independent. That is your responsibility to your wife and to your son as he becomes a man and marries. Be there for both of them, and welcome your daughter-in-law into the family while you are at it. You will find that you gain a daughter in the process.