Can Twin Parents Have Identical Kids?

More simply put, if two sets of identical twins get married, will their children be identical to each other?

Mystery Hour Question

Question: If two sets of identical twins get married, will their children be identical to each other? 

Helen and Zoe, Harrow

Answer

Name: Adam, Southend

Qualification: Geneticist, degree in genetics from University of Liverpool

Answer: No. All genes come with ‘alleles’ – dominant, co-dominant and recessive, with the most common being recessive. For example with eye colour, it’s commonly known that blue eyes are recessive; if you have one parent with blue alleles and one with brown, the child will have brown eyes as that gene is the most dominant. Although you’ll have the same genes, you won’t be identical because all genes have different alleles. However, as with all things genetic, it’s random; there is an extremely small chance that their children could be identical.