Speckled Sussex usually have a lot more white on them, this bird appears to be solid red. I can't tell if the legs are yellow or white, but legs aside rhode island red and production reds are probably the most common red chicks out there.
How old is this chick and where did you get it (feed store, hatchery, Craigslist, etc)? Knowing that will help narrow down which breeds are most likely.
Age can make a huge difference in gender guesses. Right now I don't see anything that would make me think male.