Even the most widely read and broadly educated translators cannot claim to be experts in more than a few fields. This does not mean medical translators must be physicians or that computer translators must be programmers. Translators also need to have mastered the technical aspects of word processing and communications. Translators work hard to improve their knowledge of the fields they work in by reading related material. In other words, professional translators are always learning.
Translators come from all backgrounds.
While a specialized degree in translation is useful, it is far from necessary. Ability counts more than anything else. Most translators are very widely read in their languages, and can write well. Others are fascinated by language and use translation as a way to be close to their favorite subject. Still others are experts in certain fields and use their language skills to work in that field.