What in blazes is the point of a female Transformer?
If the only way to make new bots is that Allspark doohickey, then why do the Transformers even need sexes? Of course, they don't. At least not for any reason more compelling than that untouchable axiom of the entertainment world: Sex sells. And the prospect of nice hips, a sexy/cute/sultry/FEMALE voice and boobs makes the target market that tiny bit bigger, even if it's on a fictional robot.
I don't know. I haven't watched the 2nd movie yet, so maybe there's some cute explanation for Arcee's femininity that's halfway plausible. Given the nature of the movie, I doubt it. Having grown up on Transformers, I do wonder why this line of thought never occured to me sooner.
On a related note, based on what I'm seeing the Japs and the Koreans get up to, especially the Japs, I'd put money on commercially available robot prostitutes hitting the market in less than ten years. As it is, Sega's gonna start selling wee curvaceous bots that kiss you later this year.Don't bother getting silly ideas. She's only about 38cm tall. ;-)