Why are half the Primarchs bald/ and or have receding hairlines? The Primarchs are the pinnacle of genetic engineering and human evolution, designed the emperor himself and from the gene cults of Luna

Why are half the Primarchs bald/ and or have receding
hairlines?
The Primarchs are the pinnacle of genetic engineering and human
evolution, designed the emperor himself and from the gene cults of
Luna. Perhaps their creation was even aided the chaos gods
themselves... We don't know what happened on Molech exactly...Yet, off
the top of my head I can list Horus, Lorgar, and Vulcan as bald. Most of the
others have receding hairlines and have been visited the norwood
reaper. I see Fulgrim, Sanguinis, The Lion, and russ with beautiful heads of
is it possible in the year 30,000-40,000 baldness has still not been
cured? As a young man losing his hair, I would like to know the answer to
my question.