Twins in the Bronx and the Wider World

My Mom, Daisy Schwartz Burk (1919-1981), was born a few minutes after her twin sister, Dorothy Schwartz (1919-2001). 

Their mother made most of their clothes and usually dressed them alike, as shown in this photo taken at their elementary school in the Bronx, New York. Dorothy is on the left, slightly taller and bigger than Daisy, standing on the right.

The girls were told they were fraternal twins, but they sure looked a lot--a lot!--alike.

Fast-forward to my Mom's first-born children, me and my two-minutes-younger twin Sis. Sis weighed a few ounces more than I did at birth. For special occasions, we were often dressed the same but as we got older, we were free to choose whether to do this or not.

As children, we looked very much alike. Yet as long as I can remember, our parents said we were fraternal twins. This was probably because of two placentas; newer research shows even identicals can have two placentas.

Years after our parents passed away, Sis insisted we take DNA tests to prove her lifelong, strongly-held belief that we are actually identical.

DNA proved Sis correct: we are identical twins. We rarely dress alike these days, but sometimes wear the same dress or top but in different colors. 

Did you know that identical twins are important to science? Researchers value the ability to observe and research similarities and differences in biology, medical conditions, behavioral elements, and more. In fact, Stanford University maintains a Twin Registry as part of its ongoing twin studies.

The annual Twins Days Festival in Ohio (this year, August 7-9) is not only an opportunity for twins and other multiples to mingle with other twins/multiples--it's also an opportunity for twins to voluntarily participate in on-site scientific research. Maybe Sis and I will get there one day.

Celebrating Our Twin Birthday

Today is the birthday of my twin Sis and myself. We are celebrating together and ready for another trip around the sun!

In this photo, we are tucked into our twin baby carriage and ready for a stroll in the park by our apartment building in the Northeast Bronx. 

No caption, so no idea who's who or exactly when. Still, happy birthday to us!

Twice As Nice: Identical and Fraternal Twins

As a twin and the daughter of a twin, I'm really interested in twins! Above, Sis and me when we were tiny tykes with a little bit of hair. We don't know who's who in this photo, but I'm older by a matter of minutes. 👍 

Twin birth rates

Sis and I recently did a deep dive into twin research. We learned that in the United States, twin births account for 30.7 of every 1,000 births (as of 2023, the latest statistics available). That means just over 3 percent of US births are twins, while a whopping 97% of US births are singletons. 

Yet identical twins stand out even more: only about 4 out of every 1,000 births are identical twins. In other words, identicals represent less than half of one percent of all births, worldwide. 

Identical twins are always same sex, because they are the result of one egg that spontaneously splits. In contrast, fraternal twins can be same sex or opposite sex, because they develop from two separate eggs. Here's more about the difference between identical and fraternal twins. 

Key fact: fraternal twins tend to run in families, but identicals don't. By the way, the highest rate of twin births in the world is in southwest Nigeria, where 45 of every 1,000 births are twins--primarily fraternal twins. 

One or two placentas?

Mom and Dad always insisted that Sis and I were fraternal twins, because there were apparently two placentas. These days, the common wisdom that identicals always share one placenta has been disproved: sometimes identical twins each have their own placenta!

DNA testing is the only scientific way to confirm whether twins are identical or fraternal, which is how Sis and I are absolutely certain that we're identical. Sis says she "always knew" we were identical, but until DNA came along, I trusted my Mom's belief that we were fraternal. I have to admit, Sis was correct all along. 👏