Adding to Dr Arvind, the genetics of baldness is the basic concept we need to understand. Baldness happens because of the genes people inherit from both their mom and dad. Some studies show that 80% of balding is genetic.
A key gene can come from a maternal grandpa. But this gene doesn't explain all baldness. People are just as likely to be bald if their dad or their maternal grandfather is bald.
Two new studies have fingered a small region on chromosome 20 called 20p11 as being associated with balding. This sort of thing could explain people who are bald even though their mom's dad still has a full head of hair.
Scientists don't know how this DNA is involved or even what part is involved. All they know is that people who are bald tend to have a certain version of 20p11.
One study found that having this DNA could increase a man's chances of going bald up to 4 times. If men also have certain versions of another gene, then the odds go up as high as 7 times.
The other study found a different bit of 20p11 was involved. They concluded from their study that the increased risk was as high as 3 times.
These two bits of DNA are pretty close together and are probably pointing to the same part of chromosome 20 as being important. Unfortunately, neither group found out why these bits of DNA increase someone's risk for hair loss. There aren't even any genes close by. So obviously there is still a lot of work to be done.