[quote="Actaeon, post:3, topic:291847"]
Let's clear up a few things:
1) Illigitimate is not really a term that's used any more outside of Canon Law and a few other sources. Legitimacy USED to be used to determine inheritence, and since that isn't really the case, the boy need not worry.
2) Annulments are allowed because marriages are sacraments, and like any sacrament they consist of proper form and matter. If one of these is lacking (improper) then the sacrament isn't validly carried out. An annulment does not MAKE a marraige invalid, it merely determines that there never was a valid marriage to begin with.
3) Children from a putative marriage are valid, regardless of whether or not that marriage was found to be valid in a tribunal. A putative marriage is a binding one, and is in place when at least one party believes they are wed and celebrates the marriage in good faith.
Yes. I'd add the following to your #2:
Annulments are allowed because the marriage bond either exists or does not exist between two people, and an annulment is a declaration of the Church that the marriage bond did not exist in the eyes of God (for whatever reason) between a couple who had a legal wedding ceremony (whether before the JP, minister, priest, or whoever). It is incorrect to limit annulments to sacraments. People can be validly married but in a purely natural non-sacramental marriage.
To your #1, I would add that legitimacy- or proof of blood relationship- is important in the Church mostly for computing who can and cannot be given certain jobs by the bishop (to avoid nepotism). It might have importance to do with inheritances only if there are stipulations in a will to that effect. But that is not the Church's doing, it is the testator's.