2 doctors weighed in:

Is it possible that my monochorionic diamniotic twins could be a boy and a girl?

2 doctors weighed in
Dr. Craig Keathley
Obstetrics & Gynecology

In brief: Yes

Although it has long been held that monochorionic twins are always identical (monozygotic), there are rare reports of monochorionic/diamniotic twins that are non-identical (dizygotic).
This is more common in pregnancies achieved through assisted reproduction (ivf), but is still exceedingly rare. Almost all non-identical twins are dichorionic/diamniotic.

In brief: Yes

Although it has long been held that monochorionic twins are always identical (monozygotic), there are rare reports of monochorionic/diamniotic twins that are non-identical (dizygotic).
This is more common in pregnancies achieved through assisted reproduction (ivf), but is still exceedingly rare. Almost all non-identical twins are dichorionic/diamniotic.
Dr. Craig Keathley
Dr. Craig Keathley
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Dr. Sheila Goodman
Obstetrics & Gynecology

In brief: No

Mono/di twins can only come from the same embryo, so they are always identical.
They will also have a shared placenta which can have blood vessels that so from one placenta to the other. This can cause a condition called twin-to-twin transfusion which can result in severe problems for the babies. Only diamniotic dichorionic twins can be non-identical and boy/girl pairs.

In brief: No

Mono/di twins can only come from the same embryo, so they are always identical.
They will also have a shared placenta which can have blood vessels that so from one placenta to the other. This can cause a condition called twin-to-twin transfusion which can result in severe problems for the babies. Only diamniotic dichorionic twins can be non-identical and boy/girl pairs.
Dr. Sheila Goodman
Dr. Sheila Goodman
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