Last night I attended the Everything You Want To Know About Twins lecture at UCLA. Having read Abigail Pogrebin’s book “One And The Same”, I was interested to hear from the panel of speakers she had put together – some of whom she had previously interviewed for her book. It was an exciting blend of Scientists, Psychologists, Researchers, Authors, Twins, Parents of Twins and Psychotherapists of twins! Each speaker was fascinated with twins for one reason or another, all had researched and worked with twins and twin-related issues for many, many years. And now all were one room, focusing on the science and psychology of identity.
What do we start with? How much of who we are is shaped by parents, friends and teachers? How do genes and the environment shape our behavior? How are twins different on a molecular level and what does this have to do with sexual orientation and gender identity? These were some of the questions that were posed and discussed. I will try to summarize what each of the panelists spoke about for those of you unable to attend (forgive me, this might go long)!
Dr. Eric Vilain spoke first. Dr. Vilain is currently Professor of Human Genetics, Pediatrics, and Urology and Chief of Medical Genetics in Pediatrics at the David Geffen School of Medicine at UCLA. His research focuses on what makes boys and girls different from each other, and on the interplay between genes and environment that ultimately determines sex.
Dr. Vilain’s discussion was fascinating and sometimes, quite frankly, over my head. I was never terribly good at Science in school I must confess. However, one of the parts I found most interesting (and understandable) was his topic of gender identity and sexual orientation. He began by stating that in sets of identical twins when one is gay, more than 50% of their co-twins are straight. In sets of fraternal twins, this number drops dramatically. His theory is then that sexual orientation and gender identity is, perhaps, not 100% genetic as identical twins have the same DNA make up. He also mentioned that if you study 100 gender non-conforming boys you will find that they will turn out to be 100 gay men. However, if you study 100 gay men you will not necessarily find that all of them were gender non-conforming as children.
He then went on to discuss environmental factors that modify the DNA behavior or the "epigenome". Epigenetics is not something I can clearly write about but from what I gathered during the evening and what I understand by Googling it, it is the study of heritable traits (over rounds of cell division and sometimes transgenerationally) that do not involve changes to the underlying DNA sequence.
Dr. Vilain's way of translating that science-speak was to ask us to imagine a Barbie Doll. When Barbie is happy she might wear clothes that are sparkly but when she is sad, she would wear all black. Thus, the underlying structure is the same, but the expression is modified. Identical twins have a measurable difference in their epigenome. Twins are more similar when they are very young versus when they are very old. Scientists don’t know why but suspect there may be environmental differences.
The next speaker was Dr. Thomas Mack who is currently Professor of Preventative Medicine at the Keck School of Medicine at the University of Southern California (USC). He is also the author of the International Twin Registry, a continent-wide series of comparisons between patients with chronic diseases and their unaffected twins, and the California Twin Program, an analogous program of studies among twins who differ in lifestyle or personal exposures and experiences.
Dr. Mack spoke mainly about his research and how the study of twins (particularly identical twins) has yielded amazing information in the field of various illnesses. One of the things that was most interesting to me was that among the questions asked of the twins in the study were ones formulated to be able to understand which had more exposure to germs. Thus: “who sucked their thumb more?” or “Who was always putting things in their mouth?” were asked because exposure to different viruses at a young age helps protect the body as you grow older. One of Dr. Mack’s theories is that twins who differ in terms of diseases may have epigenetic differences in terms of environmental exposure, smoking differences, dietary differences and so forth. One of his studies he discussed was one in which he found that in the Northern part of the US 25% of twin Multiple Sclerosis patients became concordant over time but in the South only 5% became concordant. Dr. Mack’s resulting theory is that the environmental difference of more exposure to sunlight and Vitamin D was a factor in this.
Dr. Laura Baker was next to speak. Dr. Baker is currently Professor of Psychology at USC, where she coordinates the Southern California Twin Register and directs a comprehensive, longitudinal study of over 750 sets of twins in a study of genetic and environmental influences in aggressive and antisocial behavior. She has a longstanding interest in how nature and nurture shape individual differences in human behavior, and has published numerous articles based on both twin and adoption studies.
Her twin study created a true paradigm shift in realizing that genes play a huge role in psychological traits such as expression, aggression, happiness and so forth. In fact, she stated that 90% of variation in aggressive behavior is due to genetic influence. For those of us with children whose level of aggression fluctuates, she pointed out that there is a “set point” for subjective well-being (basically that means you have a set point at which your body is comfortable – like with weight – and you will fluctuate above and below that point). The fact that aggression and temperament is so largely genetic was made very clear later in the evening when a mother of triplets stood up to ask about her identical daughters who “hated each other” and could only get along with their fraternal triplet brother. The mother had tried everything from therapy to separate schools to separate activities. Dr. Baker reiterated that sometimes it is just in one’s genetic make up that you are not going to mesh with another person. However, most of the panel did agree that this case was very unusual in that it is usually the identicals who bond and shut out other siblings.
The discussion then moved on with Dr. Nancy Segal who is currently Professor of Psychology and Director of Twin Studies Center, at California State University, Fullerton (CSUF). She is also the author of "Indivisible By Two: Lives of Extrodinary Twins” (which I bought and will tell you what I think of when I am finished with it) and "Entwined Lives: Twins and What They Tell Us About Human Behavior”. Dr. Segal is currently writing another book about the true story of twins who were separated at birth. One was mistakenly raised as a singleton and the other was raised with an unrelated child as a pair of fraternal twins. As a mother of twins myself I can only imagine the devastation that must have caused!
Throughout her research Dr. Segal notes that identical twins who have been separated all or most of their lives connect immediately when reunited and report feeling closer to their twin that they just met, than to the adoptive siblings they have shared their life with. She also noted that parents of identical twins are often so sensitive to the differences in personalities that they often misdiagnose them as fraternal twins!
Next on the panel was Dr. Joan Friedman. She is the author of the wonderful book “Emotionally Healthy Twins: A New Philosophy for Parenting Two Unique Children”. Dr. Friedman is also a psychotherapist here in Santa Monica and specializes in twins and parenting issues of twins. She also facilitates groups for mothers of twins and writing a new book about adult twins and attachment experiences.
Dr. Friedman spoke primarily about her belief that parents must give their twins the right to feel ambivalence or anger about their twinship. To force the fantasy of your children being best friends and loving that they are twins 100% of the time is unwise and unrealistic. She is a very firm believer in letting twins separate and develop their personalities and interests as two individuals. She also made the very strong point that the boom in multiples has created an enormous need for therapists well versed in the emotional and psychological needs of not just young twins, but for all of the twins who have now reached adulthood and middle age as well as parents and siblings of these multiples. She said she is constantly receiving calls for referrals to therapists from all over the US and Europe and there are so few people who have chosen to specialize in this area. So, for all you therapists and therapists in training: here is a niche waiting to be filled!
Next to speak was Dr. Eileen Pearlman who is a liscenced Marriage and Family Therapist in Santa Monica and the Director of Twinsight, a service specifically designed to meet the particular needs of multiple births and their families. She is also the co-author of "Raising Twins: What Parents Want to Know (and What Twins Want to Tell Them)” which I also bought last night and will post about as soon as I am finished.
Dr. Pearlman discussed the separation individuation process which is essentially when the infant begins to realize it is separate from its mother. She brought up the point that with multiples, the infants must learn to not only individuate from parents, but also from their twin. She described this “bumping up” process as the “No!” phase when a child is separating from the parent (to every question the answer is “no” – we probably all know this well) and the “Mine”” phase when individuating from their twin (also something we are all familiar with). Twins have to “bump up” against each other throughout their lives and that it is vitally important that they discover who is “me” in addition to knowing who are “we”.
There was only time for a few questions at the end. I mentioned the question about the triplets earlier. Another question that was asked was how to best help an older sibling bond with her new twin sisters. Both Dr. Friedman and Dr. Pearlman brought up the points that a) one must work hard to make sure that the formerly singleton child is allowed to bond with each of the twins separately and b) that the parents recognize that it is very hard to be “dethroned” as an only child but it can be exponentially more so when the new child is a set of twins.
The last question was a truly fascinating one for me (especially since I conceived our twins through IVF). A woman asked if there was a difference between those created naturally and those created through the use of fertility drugs. Dr. Vilain mentioned that there is a small chance of epigenetic changes with IVF and that women over the age of 37 are 4 times more likely to have fraternal twins. I wish there had been more time for questions and answers, but all in all, the evening was very informative and left me excited to learn more!
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