Imagine getting cuttings from different plants of the same species. Then bunging some of them them in the back of the airing cupbord with no light or water, most of them outside in the dirt, occassionally watering them when you remember and for a very few hiring a dedicated team of round the clock gardeners to nurture their every need.

You don't even need to ask a scientist what the reasons behind the different growth rates of the plants are. A child could figure it out. The fact that these very cleaver very rich people would pin it on genetics is literally the best argument going against their so called genetic superiority.