For me most were made. They became on who they are right now through time, learning and experience, etc. I think most struggled when they are starting until get polish day by day. Still, we can't deny there are people who were born talented and some became good with daily practice. In short, you can become skillful too even if you weren't born as a trader or doesn't have any in your clan through practice.
You are right. Gamblers are themselves making as traders and skill by birth is very rare.
There are some skills are possible when we are born but I believe trading kind of technical skills are not possible this way. It will be possible only through continuous learning and practice. But, analytical skills are possible by birth and we cannot ignore the importance of having good analytical knowledge for trading better. It is all about good observations and spotting out things at right times.