Haven't read all the pages, so don't know if this was discussed earlier, but here's my two cents...
Core D&D, for better or for worse, is a game of moral absolutes. This is the only way the alignment/outer planar/alignment subtype/holy weapon/etc. system presented in the D&D cosmos can be internally consistent.
A "lawful good" sword, for example, bestows a negative level of anyone of chaotic or evil alignment that picks it up. Suppose for a moment that the sword is an intelligent one (work with me here). What happens when Character X picks it up?
Well, if you subscribe to absolute morality, it's pretty clear. Either Character X is chaotic/evil or he is not. If he is, he gets a negative level (or two). If he's not, he doesn't.
But if your world is based on culture-based morality, it's not so clear. Suppose the intelligent sword's "culture" requires chastity of paladins. Character X is a "paladin who is required to by his religion to spread his seed far and wide." Does the character get to determine whether or not he's "lawful" and thus avoid the negative level? Does the sword? If the sword makes the determination and bestows a negative level on him, what happens if the sword is NOT intelligent but crafted by the same culture?
If the "sword" determines it, now you have to track every single cultural moor of every culture that crafted magic swords! If it doesn't, you have the odd spectacle of a "lawful" intelligent sword being dragged along by a character that it clearly believes to be non-lawful without penalty.
Now, if you wish to scrap the alignment system, that's a whole 'nother ball of wax, but the point is... in "core/default" D&D there are moral absolutes (the Book of Vile Darkness, IIRC, speaks to this fact).
A culture that preaches "sow your wild oats" as a tenant of its cultural norms is therefore incapable of producing paladins if "sowing your wild oats" is an inherently chaotic act.
Thus, it falls to the individual group to define a certain set of moral absolutes that a paladin must adhere to, regardless of culture. In other words, you can't have two paladins with diametrically opposed moral codes on the excuse that they come from different cultures and have a different view of "what is lawful." The system simply isn't set up that way.
Whether or not you feel that "sowing your wild oats" should be considered outside the realm of "lawful" is, of course, left to the discretion of your own gaming group, but in archetypal medieval/fantasy culture, doing so is generally not considered "lawful" for many of the reasons mentioned above... not the least of which is "fidelity" (not speaking here strictly of "marital fidelity" but rather a sense of responsibility and duty toward certain people, and I think it's a fairly compelling argument that you are responsible for any life you decide to create/sire - so a paladin who wantonly has sexual relations but does not follow up and/or support and raise and protect his children is guilty of neglect of duty to his offspring... thus, infidelity).
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FWIW I see the paladin's code as a sort of modified "Asimov's laws of robotics" - i.e., a set of laws, which when applied to any given situation, will tell the paladin either how he must act or that it doesn't matter how he acts (e.g., applying these laws tells you that it doesn't matter whether or not you order the roast mutton or boiled chicken in most circumstances - it's a neutral choice unless church or local law proscribes one or both).
Law 1: The paladin will never harm an innocent, nor through inaction, allow an innocent to come to harm.
Law 2: The paladin will always offer evildoers a chance to repent in order to bring them from guilt to innocence except where doing so would violate the first law (e.g., if the villain is about to offer up a child sacrifice, you do not wait to save the child in order to offer the villain a chance to repent).
Law 3: The paladin's conduct must always be honorable and truthful, except where conducting oneself honorably would put him in violation of one of the first two laws (e.g., when you stumble upon the villain about to offer up the child sacrifice, you are permitted to attack immediately; you do not have to waste the time announcing your presence and challenging him to a formal duel while he kills the child).
Law 4: The paladin will protect those/that to whom/which duty binds him (including deity, kin, church law/tradition, kith, and local law in that order) except where doing so would put him in violation of one of the first three laws (i.e., the paladin cannot lie to save his dishonorable comrades as this puts him in violation of Law 3; where the paladin must choose between local law and his "church law", he sides with his church, etc.).
Law 5: The paladin will seek self-preservation only when it does not violate one of the first four laws (i.e., a paladin is permitted to withdraw from danger, but only after all others to whom duty binds him have already withdrawn AND provided he does it in an honorable fashion AND provided there are no innocents put at risk by his withdrawal.
From application these five laws, just about any morally sticky situation can usually be handled with relative confidence as to whether or not the paladin is acting as a paragon of "lawful good."
Using this standard, a paladin who sows wild oats, under most circumstances, would lose his paladinhood as he is in violation of the fourth law, neglecting his duty to kin (unless, I suppose, the paladin's deity personally commanded the paladin otherwise; church law/tradition is lower on the heirarchy than duty to kin so culture is not an excuse).
Thoughts?
--The Sigil