Not only that, katrinkadee, but the Czech sentence contains no demonstrative (such as to, ty, etc.) That is a pretty good indication that 'the' should not be arbitrarily inserted into the English.
In translating, you sometimes need to insert a "the" into the English, even when there is no demonstrative in the Czech, in order to be idiomatic; but you should not do so routinely.
But I probably get what you mean.
Ženy ho/jej chápou. relates to some particular object in masculine or neuter (ten dopis, ten článek, to sdělení, to psaní) .
Ženy to chápou. relates to some "it". Some concept or abstract or concrete object, the thing we were discussing... It can be a clause "Ženy chápou to, že...".