A recent conversation brought up a very intriguing question that I don't think has an easy answer and I can't believe I haven't thought about before: Who would win in an all-out brawl between Maggie Simpson and Stewie Griffin? I'm sure this question has been asked before given the many, many parallels between the two shows, but I feel fairly qualified to throw in my two cents on this throw down.
In keeping with tradition of ladies first, let's start with Maggie. A number of years ago, America debated and placed bets all summer long in anticipation of who shot Mr. Burns in The Simpsons cliffhanger season finale. Who would have thought it was Maggie? The youngest Simpson's inability to speak (only ever saying "Dada" and "sequel" as a baby) and ability to not arouse suspicion affords her the element of surprise, allowing her to sleep with a gun under the pillow of her crib, just in case her dad should get in trouble with the mafia on their front lawn.
Stewie on the other hand has never been subtle about his plans for world domination or desire to kill his mother. He has tried to kill her in numerous episodes, but poor timing, bad aim, or the rare good parenting always gets in the way. The most infamous of his threats come to fruition was recently when he actually followed through (sort of) on his murderous plot. He followed his parents onto a cruise ship and shot Lois at the rear of the boat where she fell overboard and was lost at sea and presumed dead, at least until she burst into the courtroom Kool-Aid Man style, pointing to her youngest as her attacker. Turns out the whole thing was a virtual reality simulation of said events, voiding all that transpired.
So the score so far I think goes in Maggie's favor, since she actually shot someone while Stewie's gun battle was fantasy. Let's look at more minor events for further evaluation. Both babies have other baby arch-nemeses: Maggie has the unibrow baby Gerald, Stewie has half-brother Bertram. To my knowledge, I don't believe Maggie and Gerald have ever done anything more than exchange menacing looks, but Stewie used his immense brain power to shrink himself and enter Peter's body to destroy what would become Bertram. They inadvertantly become pseudo-friends and Stewie lets him live to become a specimen at the sperm bank, and they eventually resume their rivalry outside the womb. I'd say this round would go to Stewie since he is showing more determination in dealing with the enemy.
So while Maggie has the experience, she lacks malicious intent. Stewie has the drive, but lacks follow through. Both have above-average planning skills for other children their age: Maggie organized a Mission:Impossible-esque crusade to retrieve pacifiers for an entire daycare, Stewie built a machine to alter the weather in an effort to prevent broccoli from growing just so he wouldn't have to eat it.
Taking all of this into account, here is my conclusion. In a no weapons battle, I'd go with Stewie since he can walk consistently without falling down. In a shootout, my money would be on Maggie since she has more experience and better aim than Stewie. If the babies are allowed to choose their weapons though, it has to be Stewie simply because he has a mind for inventing deadly devices. In the end though, they are still both babies and in any prolonged battle (which this would be since they are so evenly matched) they would probably both get tired and the match would end not with a victor, but with a nap.