doble prima

a few posts ago, i recalled a question i once asked of my gram. could identical twins who married identical twins have identical children? if so, what are the odds? it wasn’t a throwaway line to make a point. i really asked her that once, and i genuinely wanted to know. she acted like she thought i was trying to wind her up, but it’s also possible, looking back, she didn’t quite know what to make of me or my question. 

it’s a weird thing for a kid to wonder about, i suppose, but it came from a growing fascination i had with, for lack of a better word, genetics … in the VERY lay sense. see i was, at that point, still an only child—my blended family of three brothers and a sister would come later—and i bemoaned my only-childness intensely.

i had another unusual family situation, though, that helped fill the sibling void i felt so acutely. i had what’s known as a double cousin. what is a double cousin, you ask? well, a double cousin is when a set of siblings has children with another set of siblings. the resulting children are known as double cousins.

my mom (the fourth child of five) married my biodad (also the fourth child of five). then my mom’s sister (the baby of the family) married my biodad’s brother (also the baby). both couples had a child, and presto chango … double cousins.

even when we were really little, meg* and i knew our relationship was unique, more like sisters than cousins. we shared all the same grandparents, all the same cousins and all the same aunts and uncles. the rest of our cousins had entire other families that we knew hardly anything about, while we shared every holiday, every gathering, every vacation, every everything because there was no other family to split time with.

our families dressed us alike, and we did sibling things like create a secret language and beat each other up while blaming the other one for starting it. like a sibling, she has been there from the very beginning (well, since 14 months), and she knows my story. there’s no need to explain things to her or give context. she was there for the vast majority of it. 

of course, i didn’t know anything about genetics when i was seven or that meg and i truly are more like sisters than cousins. it turns out that biologically we have twice the DNA in common than typical first cousins do—25 percent to be exact (the same as half-siblings). i’m sure that our unusual family tree was what set my mind to the idea of two sets of identical twins having children with each other. (if you’re interested, identical twins marrying identical twins is a thing, and their offspring would be biologically indistinguishable from full siblings. in other words, they would share 50 percent of their DNA.)

it’s been on my mind a lot lately because of the genetic counseling i’ve done as part of my cancer treatment. they ask you about your entire family and everyone’s health history. it’s always fun to explain double cousins to someone for the first time. most people find it somewhere between mildly and intensely confusing, but the genetic counselor was unfazed. she’s probably seen it all.

i have been completely estranged from my biodad for over ten years now (that’s another post altogether), and so to prep for my appointment with the genetic counselor, i knew i would have to be creative to get family information from him. without hesitation, i called my brother dale* and asked if he would reach out to our dad and do some fishing for me. he agreed but asked what the pretense should be. i said he could pretend to be doing some genetic testing on himself and to need information. the funny thing is, this brother is technically a step-brother, adopted by my biodad. we (and they) share no DNA. but in that moment, i completely and utterly forgot that fact. he’s just my brother, no qualifiers. he’s 40 now, but to me, he’s still knobbly knees and superhero undies … my baby brother. i turn to him in good times and bad, and i couldn’t love him more if we shared 100% of our DNA.  

that’s the thing about genetics. it’s so important, and it’s not important at all. what we enter life with and what we adopt to move through it are linked but not inextricably so. we make a lot of it up as we go along, and much of it happens to us without our bidding or control. that piece is ineffable and stubbornly resistant to tabulation. but it’s also what can make life unexpectedly rich and meaningful.

* i’ve changed names for privacy.

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