"My son is born!"
Translation:Min søn er født!
The English form of the word, "born", does not have a past version of the word - the same root word is used for past and present tense. The Danish form of the word is the same way, so, just as in the English version, you have to look at the context of the sentence to determine the tense of the word. In this case, the son has already been born, so it is, in fact, past tense. Irregular verbs are brutal, aren't they.
I don't agree that this is past tense. It is present tense indicating a current state: "My son is here." "My son is on earth now." .... "My son is little." "My son is blond." "My son is loud." etc.
Obviously, this works differently in English as compared to Danish, German, French...