it runs in the family

Founding father of Singapore, our first Prime Minister, revered Minister Mentor and now professor in Genetics explains:

“That is the way the world is. I have explained this. I think I lost votes after I explained the awful truth. Nobody believed it, but slowly it dawned on them – especially the graduates – that yes, you marry a non-graduate, then you worry about whether or not your son or daughter is going to make it to the university!”

Paraphrasing,

Graduate + Graduate = Graduate
Graduate + Non-Graduate = Poly Grad
Non-Graduate + Non-Graduate = CDC client

Graduate + Graduate + Non-Graduate = ??

Of course the old guy knows what he's talking about. Prime ministering runs in the family.