@ Urouge OK it would not be strange for there to be contacts protected by layers of secrecy and specific people that are thier contact people, like in a Bond movie, so I can certainly see several scenarios where a woman could have come into contact with Dragon and not be known to his compadres.
Here's a scenario that could work even if they did know her, esp if they knew anything about what happened with Ace, etc, and no reason to think they didn't, since Garp isn't known for his discretion with family members–I could easily see him telling the whole tale to Dragon--she could have been part of his larger crew, sent off on a mission from whence she never returned, already pg. with Luffy when sent, but not visibly so. Perhaps noone knew about their relationship but Dragon himself, and perhaps the people who knew her personally were told she'd been killed. Don't tell me you've never heard of a girl bundled off to the country to have a kid in secret--there's plenty of time to hide someone after finding out they are pg, and of course Dragon would understand the danger to his anamorata and his progeny. He would have understood enough about it to even hide the relationship itself from everyone else. If it was a fellow revolutionary, they could easily have cooked up a fake "mission" as an excuse to bundle her off (to Windmill village, or elsewhere) until she delivered, and if she were anything like Dragon she may have demanded to be allowed to return to active duty afterwards, perhaps deliberately elsewhere from Dragon--out of loyalty to the cause or to protect the baby even further--both reasons work--but somehow she never retrurned, or she went elsewhere to further hide the relationship with Dragon and the baby. It seems frighteningly easy to disappear in OP world--look at Sabo, lol.
Editing in another scenario that could work, too--He had a love interest, and used his occasional trips for revolutionary concerns to visit when time and circumstances allowed. On one of the visits they managed to conceive a child, and said child was bundled off for the child's protection, blah blah blah.
Putting your life on the line every day can make your... thirst for life, in all it's pemutations, esp in terms of doing what comes naturally, all the stronger. Many marriages are consumated and many children are conceived right before deployment. It's not unprecedented in the story, since Gol D. Roger knew he was dying, presumedly, when he had his fling with Rouge. So, essentially, and with all due respect, the idea that he went off and had a kid three years after Ohara doesn't actually strike me as odd, since I sincerely doubt it was a planned pregnancy.
I think eventually we will learn that story, and I'm very curious about it. The fact that Dragon was already heavily involved in the revolution when Luffy was born does nothing more that confirm the reason Garp ended up raising him for me...
Of course I'm very tired and jsut had a tough day, so if I misunderstood your post, then... Nevermind. LOL