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Name: Amelia
Status: Other
Grade:  Other
Location: N/A
Country: United States
Date: June 2006


Question:
I was told I have fraternal twin boys. However, I have been told that identical twins may have two placenta and this, I believe, was the bases for calling them fraternal. Even though their eye colors are slightly different, is it possible that the boys are identical?



Replies:
Twins either can be either Monozygotic - i.e., twins developing from a single zygote. Such twins are genetically identical (hence also called as Identical twins). These twins are of the same sex and look very much similar to each other.

Or Dizygotic - i.e., twins developing from two separate ova and sperm cells. Such twins are also known as "fraternal twins". There is a 50% chance that both of them being the same sex (male, male or female, female) or different sex (female, male).

All monozygotic twins are of the same sex but NOT all the same sex twins are monozygotic! Placenta or their number do not influence characters such as eye color in a developing foetus.

P. Kumarasamy



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