The gecko you have pictured is Gekko ulikovskii known as the Malaysian Gold gecko, Yellow-backed gecko, or the most common name I have heard it under the Vietnamese Golden gecko. The specimen you have pictured is most certainly a male. Males have a bright yellow coloration on the dorsal area like yours is displaying, females tend to be a more brown natural color. I believe they have the color differnce for the same reason most waterfowl do. The males need to be bright and vibrant to attact the various female mates (kind of like male anoles use a dewlap display to attract females) and females need to be less vibrant and more earthy tones to avoid getting caught by predators keeping the eggs she carries safe. Just a theory... I have worked with Golden geckos for sometime mostly with imports as Captive bred specimens are rarely availible, mostly due to the fact they are availible from most importers as low as a couple dollars. Some people I know whom have worked with them say they have been able to get the relaxed enough to handle, not by my experiences. They tend to like a lot of non-citrus fruits like apricot, peach, banana and honey concoctions. I make a nice diet that Monte from Powergeckos once put up for Cresteds, it depends what I have in the kitchen but it works great. I take a peach, apricot, banana, and any othr non-citrus fruits with some calcium suplemnt and some honey in a blender, mix til pureed and spread on a cookie sheet with wax paper on it. Freeze it and break into chunks to use individually and let thaw before serving. Who wouldn't like that eh? hey also eat a variety of insects like crickets, waxies, and silks. Anyhow hope any and all this helps with you gecko.
Mother Gecko- Reptiles