I have come to this conclusion through my clinical experiences working with twins who have suffered differing types of estrangement, from fixable to totally unresolvable. My complicated psychological theory is based on the reality that twins share an identity as twins. In addition and hopefully, each twin has his or her own individual identity that helps him cope and be successful in the world of non-twins. Twin identity based on shared life experiences and shared parenting creates identity confusion, enmeshment and interdependence as twins grow into adults. I wrote about this in more detail in my book, “Twin Dilemmas: Changing Relationships Throughout the Life Span.”

Here is how I translate my ideas about adult twin identity confusion into action words.

• Whose problem is it to take care of our older relatives now?
• Is this bill/check/invoice or dinner party your responsibility or mine?
• If you look fat do I look fat? Why do we need to look alike?
• Do I have to share with you my happiness/sadness?
• Am I a bad person because you are angry with me and want me to act differently?
• Please don’t treat me as invisible.
• Am I borderline because my sister says so?
• Why can’t I be important like my brother?
• Who was and remains the favored child?
• Why can’t my husband get along with my twin and her family?

Of course, twin confusion about responsibility and ownership begins early in life. My mother was featured on a morning radio show “The Breakfast Club” in 1946 because she did not know which twin she was feeding. Her dilemma was seen as an amusing news story. But looking back on her confusion, I can only imagine our (me and my twin’s) confusion as infants and toddlers and as we grew into adults. And from working with twins of all ages throughout my career I am totally sure that twins are painfully confused by their twin identification, which results in anger and estrangement. Longing for childhood intimacy, twins continue to struggle with each other.

Non-twins cannot understand the intensity of emotion that goes into setting limits for your twin. While twins have been idealized in our culture, the reality of twins’ relationships is very different and certainly not ideal. Twins can be mean to each other and call one another names. Twins can steal one another’s clothes without remorse. Sometimes twins have sexual experiences with each other’s partners, which causes serious damage to their attachment no matter what else ensues. Treating your twin as if they do not exist is another damaging interaction between twins, which is unresolvable because of the intensity of feeling. I know of a twin who was so angry with his twin brother that he threatened him with a gun. Of course, there is no hope for resolution now; there is too much danger.

Recently, I had a referral from twins who wanted to get along after many decades of fighting. These thoughtful and educated women said the most hateful things to one another and argued so ferociously that anything I said made their interaction worse. In their words, they were continually triggering one another. I felt as if they were five years old and trying to get me to take their side. One/each twin wanted to be favored and right. I was frightened by how their intense anger could disrupt each other’s sense of self. Watching their fighting and enragement will be hard for me to forget.

My twin sister and I fought and were critical of each other’s choices when we married and pursued our own very different lives. For over 20 years we barely talked to each other. But we did not try to pull each other’s hair out or sleep with our twin’s boyfriend to get back at one another. I have talked with families about the twin wars that are so common between twins and families and twins and family. Fighting is not a way for adult twins to resolve their differences. Understanding and accepting that this fighting is a twin phenomena will help.

I say, “Hurting your twin is hurting yourself,” as a warning to help twins stop fighting and being mean to each other.