First of all, I do not believe in horoscopes or any such nonsense but in this situation it makes the story better. Feel free to take it out if it gets too messy.
I was born on June 2nd and my dad was born on June 3rd. This makes our astrological signs “Gemini” or Twins. He is an identical twin. I gave birth to fraternal twins. He is a twin-twin and I am a twin that had twins.
It gets better. My Aunt (father’s-sister) had identical twins. My mother’s Aunt had fraternal twins too (which is where I got them from). After my mother divorced my father, she married the boy of boy/girl fraternal twins. So I have twin second cousins, twin cousins, 2 twin dads and I’m an astrological twin that had twins.
What are the odds of more twins being born in my family?
Below are the extended notes provided by cognitive psychologist and statistician Barbara Drescher for use in Skepticality Episode 000. Take a look and leave your comments below. Also, please be sure to listen to the podcast for our own hilarious commentary. Also, visit Barbara’s blog ICBS Everywhere, and Insight at Skeptics Society.
Well, I would say that the odds of more twins being born might be pretty good, but not much higher than in anyone else’s family. Of course, one would have to define and learn quite a few things before even trying to come up with an actual number, including what is meant by “family” (siblings? offspring?) and the ages and intents of those involved.
But there are a few things to talk about nonetheless.
First, the author notes that two of the cases of twins are identical, and one case is a step-father. Identical twins occur as randomly as astrological signs and one has no blood ties to a step-father, so these factors are independent–they have no influence on whether twins will occur in a family. Fraternal twins, on the other hand, do run in families, as hyperovulation is a genetic trait, although one does not receive genes from aunts/uncles. If genetics are to blame, the author’s chances of having fraternal twins on a subsequent pregnancy is now double. In addition, the age of the mother is a factor–the older the mother is, the more likely fraternal twins will occur.
All of that said, fraternal twins can also be the result of fertility treatments. This introduces a controllable factor that can increase the odds of twins dramatically. If fertility treatments are involved, genetics can’t be blamed.
According to Babycenter.com and several other online sources, the most recent data shows about 1 in every 30 births today are twins (about 3.3%), with only a about 10% of those being identical. So, about 3 in every 1,000 births will be twins born under Gemini.
Having that many twins in a family depends on many factors such as the size of the family, but I do love the idea of introducing someone as a twin twin with twins (yes, I know author isn’t a twin herself, but I took some license).