Finally we have proof! Doctors often misinform parents about zygosity

Throughout my pregnancy, my OB and the ultrasound technician told us our boys were absolutely, positively, no-doubt-about-it fraternal. Yes, my doctor said, identicals can have separate placentas and sacs, but mine implanted too far apart to be identical.
Their placentas were on polar opposite sides of the uterus.
Identical twins implant more closely, he said.
He was wrong.
And he has company.
In a new study from University College London, researchers found that doctors wrongly told parents their identical twins were fraternal in 27.5 percent of the cases. Like my guys, those twins had their own sacs and placentas.
The study also found that 2 percent of parents were wrongly told their fraternal twins were identical because doctors did not realize their separate placentas had fused into one. Overall, 15 percent of twin parents were misinformed about zygosity.
I have long suspected the statistics involving identical twins are skewed.
This proves it.
So many parents find out long after birth that their twins are identical through DNA testing. That information is never reported to any statistic-gathering source. If this study hold true in the US, then statistics showing the odds of having identical twins is about 3 in 1,000 are way off.
It has become a game on online twin forums: Guess whether the twins are identical while the parents await results of DNA testing. In most every case where parents of di/di had trouble telling their twins apart, the results showed they were, indeed, monozygotic, or identical.
I have come across just as many parents of look-alike twins in real life and virtually who decline testing despite their gut feelings. Either they can't afford the $100 to $200 fee or they see slight differences between their twins and accept those as evidence their twins are fraternal.
We could have done that do that with our guys.
Matthew has a slighter build and a thinner face. Jonathan is much more muscular and has a rounded face -- a little more body fat in his cheeks. But that scenario is true of most identicals. One usually has a slightly different facial shape than the other.
In some of those cases, parents brushed off their identical suspicions because their hospitals "tested" the placentas and the results showed they were dizygotic, or fraternal.
Our own doctor fell for that until I pressed him for more information and he checked with the hospital.
It turns out hospitals check only whether placentas are fused. The hospital techs either definitively declare the zygosity according to the results or the pass the results on to doctors or midwives who were told in medical school that two placentas equals fraternal.
The doctors or midwives then pass that misinformation on to parents.
Remember this: hospitals DO NOT do DNA testing.
In the defense of OBs, midwives and ultrasound technician, zygosity is irrelevant in caring for pregnant women. What matters is only whether there is one placenta or two, and one sac or two. So they really don't need to know for medical purposes.
That doesn't, however, excuse the giving of misinformation.
In our case, a fellow soccer mom who was a neonatologist educated me.
She told me that identical twins implant separately when the split occurs immediately after conception -- within the first few days. Matthew and Jonathan probably became two far up in the fallopian tube, she said, allowing them to fall and implant independently, just like fraternal twins.
At the very least, our OB should have told us he didn't know.
He should have known that he didn't know.
All doctors, midwives and ultrasound technicians should know that they can't be certain with same-gender twins until after the babies are born. Though the information is medically irrelevant during pregnancy, there is no excuse for being misinformed about something so relevant to the field in general or for passing that information on to parents.
None.

Zygosity: why does it have to be so hard?

When we first found out our twins were, indeed, identical, I believed that the intial mistake in their zygosity was just a fluke. Their placentas were, after all, on opposite sides of the uterus. According to my OB, it was so highly unlikely that they were identical that he hadn't even considered it.
From what I understood, cases like ours were rare.
Not so.
Over and over again, I hear of twin parents who are told that their twins are fraternal, but who still simply cannot tell their twins apart. They post photos of their twins on online bulletin boards, hoping for answers.
Like us, those parents are told that the placentas were tested at the hospital. The babies can't be identical: just look at the results, the doctors say. The parents scratch their heads and try to persuade themselves that the hospital and the doctor must be right.
What doctors don't say is exactly what kind of test the hospital has conducted.
Here's what they do: Hospital simply conduct a physical test of the placentas. The lab tech studies the membranes to determine whether they were two fused placentas or one shared placenta.
That's it.
DNA has nothing to do with it.
In our case, that was a no-brainer.
Matthew and Jonathan each had clearly distinct placentas and, so, the results on my OBs computer said "fraternal." He assured us that many twins look identical when they are born and that they would differentiate as they got older.
That never happened.
If anything, they look more alike.
We finally had our boys tested when they were infants. It was easy. We received a kit in the mail for about $170 and rubbed large swabs gently inside their cheeks. We put the swabs in the test tubes the lab provided and mailed them off in the box the company gave us.
The results were supposed to take three weeks.
We learned the boys were identical a week later.
Every single one of those parents I have met online later learned through DNA testing that their instincts were correct: their twins (and sometimes two of their triplets) were indeed identical despite the protests of their OBs.
I'm not sure why some OBs still subscribe to the old theory that two placentas equals fraternal twins. Their information is outdated and so much evidence exists to prove that their methods are faulty. Just take a look at this 1999 study. The author urges OBs to change their evaluations if for no other reason, because the twins simply have a right to know.
So why does it have to be so hard?