This seems to be pertinent to my situation, from the CE entry on "Defect of Birth."

The defect of illegitimate birth may be cured in four ways: (1) By the subsequent marriage of the parents; (2) By a rescript of the pope; (3) By religious profession; (4) By a dispensation.

(1) The subsequent marriage of the parents of an illegitimate has, by a fiction of law, a retroactive power which carries the marriage back to the time of the birth of the offspring and covers it with lawful wedlock. In order that the fiction of law may produce this effect, the parents, at the time of the conception or, at least, at the birth of such offspring, must have been capable of contracting lawful marriage. Therefore, this more of legitimation is applicable only to natural illegitimates. And these, though legitimized by the subsequent marriage of the parents, or even by an Apostolic dispensation, are forever excluded from the dignity of the cardinalate. (2) A rescript of the pope confers legitimacy in so far as it is required for spiritual affairs throughout the universal Church. (3) Religious profession in an approved order cures the defect of illegitimacy. Religious profession is the taking of the solemn religious vows; but the simple vows taken after the noviciate in some orders produce a like effect. This mode of legitimation only renders illegitimates capable of ordination. It cannot be extended to dignities or even to regular prelacies. Hence, illegitimates thus legitimized are still debarred from the position of abbot; and women of illegitimate birth, for like reasons, cannot hold the position of abbess or prioress. (4) A dispensation granted by a lawful superior removes the defect of illegitimate birth, but only for some express purpose. It is not a mode of absolute legitimation. The purposes for which it is granted must be specified; as for promotion to minor orders, to major orders, to a specified benefice.

A dispensation of this kind runs counter to the common law. It is of strict interpretation, and therefore cannot be extended from like to like or from greater to less, unless the one is included in, and presupposes, the other. Such is the case when a dispensation is conceded to an illegitimate to receive Holy orders. Such orders require a title, and this title is, in canon law, a benefice. The pope is the lawful superior for the universal Church, and as such he can dispense in all cases where a dispensation is possible. Bishops and other prelates having quasi-episcopal jurisdiction can dispense their own subjects, in this matter, for first tonsure, minor orders, or a simple benefice; but not for major orders, even though the illegitimacy be occult. This episcopal, or quasi-episcopal, jurisdiction does not extend to a benefice which was immediately possessed by the father of the person seeking the dispensation, nor to a benefice which by custom or privilege requires its possessor to be in major orders.

My reading of this tells me no. So, it appears for the SSPV, CMRI, and other de facto sedevacantist orders, I could not attain major orders. For sedeplenist groups, I probably could.

Doesn't Baptism take care of that?

Jim said:

My parents were not ecclesiastically married, only "legally/civilly." Under the 1917 code, this is an impediment to the priesthood. If I applied, say, to MHT Seminary or the CMRI seminary, could I be accepted? How would a dispensation be obtained?

If you're saying you're illegitimate, I'm guessing your parents, or at least one of them, was a baptized Catholic who married outside the Church?  

Yeah, just write CMRI a letter, I am almost 100% positive that in times like these, they won't be too choosy.

I don't think illegitimacy was an impediment to being a brother.  Wasn't St. Martin de Porres illegitimate? He was a Dominican brother.

Also, wouldn't granting a dispensation like this require jurisdiction?  How could a sedevacantist bishop do that?

Augustine Baker said:  

I can't imagine that the Sedes are going to follow the old code of canon law to the letter.  They were meant for conditions involving a highly organized, coherent and relatively uniform Church where dissent was kept underground or studiously ignored, among other things.

Like the SSPX does?  Where is it written in canon law that you can disobey and / or ignore the local ordinary without probably even checking whether he's an actual heretic or not?  Where is it written in canon law that a third-order can overrule decisions of other bishops and priests in the Church ( since you mistakenly think VII is the Church ) when it comes to marriages, to the point of setting up its own tribunal?  

The sede interpretation of epikeia makes FAR more sense than yours, and that is incontestable.  No schismatic overtones, simply emergency actions, salus animarum suprema lex.

You guys try to have it both ways.  It doesn't work.  SSPX theology is a mass of contradictions.  While sedes may take advantage of epikeia more or less liberally, there are no contradictions.

As usual Raoul is right, and I want to add that it is Divine Law that the Catholic Church must not fail in their most fundamental obligation to save the souls.  

There are many times when a church law is not longer applicable because it no longer applies and might even hinder the greatest law, which is to Save Souls.    

Augustine Baker said:  

Quote

I can't imagine that the Sedes are going to follow the old code of canon law to the letter.  They were meant for conditions involving a highly organized, coherent and relatively uniform Church where dissent was kept underground or studiously ignored, among other things.

Like the SSPX does?  Where is it written in canon law that you can disobey and / or ignore the local ordinary without probably even checking whether he's an actual heretic or not?  Where is it written in canon law that a third-order can overrule decisions of other bishops and priests in the Church ( since you mistakenly think VII is the Church ) when it comes to marriages, to the point of setting up its own tribunal?  

The sede interpretation of epikeia makes FAR more sense than yours, and that is incontestable.  No schismatic overtones, simply emergency actions, salus animarum suprema lex.

You guys try to have it both ways.  It doesn't work.  SSPX theology is a mass of contradictions.  While sedes may take advantage of epikeia more or less liberally, there are no contradictions.

In other words, you can do whatever you want, believe whatever you want and no one's going to hold you accountable for the most part.