Advertisement

What is the difference between fraternal and identical twins?

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Fraternal twins occur when two separate eggs are fertilized in the same cycle—often the result of ovarian stimulation or multiple embryo transfer during fertility treatment. Genetically, they're no more similar or different than any other siblings.

Identical twins, which account for one-third of twin births, come about when a single fertilized egg subsequently splits in two. Identical twins share the same genes, but are never truly identical.

Depending on when the embryo divides, identical twins can be completely separate, share a placenta, share a placenta and an amniotic sac, or be conjoined (Siamese).
YOU: Having a Baby: The Owner's Manual to a Happy and Healthy Pregnancy

More About this Book

YOU: Having a Baby: The Owner's Manual to a Happy and Healthy Pregnancy

Can I get a cavity filled while pregnant? Will avoiding spicy foods make my kid a picky eater? Can I really increase my baby's IQ while she's in utero? Whether you're pregnant for the first time,...

Continue Learning about Genetic Disorders and Birth Defects

Stemming the Tide of Stem Cell Scams
Stemming the Tide of Stem Cell Scams
In April 2019, the Federal Trade Commission returned almost $515,000 to consumers who bought deceptively marketed “Amniotic Stem Cell Therapy” between...
Read More
What is Turcot syndrome?
Dr. Vincent T DeVita JrDr. Vincent T DeVita Jr
Turcot syndrome is a rare inherited condition in which people are at increased risk of adenomatous p...
More Answers
What are stem cells?
Jumo HealthJumo Health
Stem cells can become any type of cell. Stem cells that live in the bone marrow are called hematopoi...
More Answers
When Should I Get Genetic Counseling for Genetic Disorders?
When Should I Get Genetic Counseling for Genetic Disorders?

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.