Question: The amount of DNA in the nucleus of a human egg and sperm cell is the same. However, when new humans are formed, they receive more DNA from the mother than from the father. Is there any specific reason of why this happens?  

Paul McKeegan answered on 7 Nov 2017:

Another great question!

So it is both true and false that we get more DNA from our mothers.

We get an absolutely equal amount of NUCLEAR DNA from both parents – 23 chromosomes from each which line up in the fertilised egg to make a unique genome and a unique organism.
But we get ALL of our mitochondria from the egg and mitochondria have a tiny circular genome which has 37 genes. This is a leftover from when mitochondria were single-cell bacteria doing their own thing, millennia ago. So we get all of our mitochondrial DNA from mum.

That said, mitochondrial DNA doesn’t really affect any of our defining characteristics and the genes code for some, but not all, of the proteins involved in mitochondrial function, whereas the nuclear DNA has about 20,000 genes which cover absolutely everything!