This has been a thought running through my head for quite sometime. Based on recent chapters, I’m beginning to believe that Luffy’s Mom is/ was in fact a celestial dragon. Dragon falls in love with a celestial dragon. This taboo/ controversial relationship leads to the creation of our beloved protagonist. In the perspective of Luffy’s Mom, I would think that she either tried to hide the pregnancy, and simply gave Luffy away to keep her status as a celestial dragon, or she gave birth to Luffy and was executed for her frowned upon relationship with Dragon. This explains the hate Monkey D. Dragon has for the celestial dragons as a whole. But still that Dragon tattoo covering that slavery sign, and Dragon hating the Celestial Dragons and World Government, are our only clues. But since we haven’t seen or heard anything from his mother, it’s hard to say much about it for now.