Monozygotic twins.

A man & women who both appear normal have a child together, who has sickle cell anaemia. The woman becomes pregnant again and is told that she is carrying fraternal (dizygotic) twins. What is the probability that both of the couple's twins will have Sickle Cell Anaemia :-

Dizygotic twins are a result of

How many eggs are released by a human ovary in a month ? How many eggs to do think would have been released , if the mother gave birth to identical twins ? Would you answer change if the twins born were fraternal ?

For an organ transplant, it is an advantage to have an identical twin.

Identical twins are born when:

Why are no two individuals identical except the identical twins?

Slight difference in identical twins support the hypothesis that

At the time of ovulation usually a single ovum is released. However, how many ova are released in case of identical twins and fraternal. Twins respectively?

Give technical term : Non-identical twins produced by the fertilisation of two eggs.

Concordant type of twins are