Martha Roberts was the attractive daughter of Professor Roberts, who had tutored young protégé Darrel Dane in his home laboratory. During the summer of 1939, Martha was blackmailed by a criminal named Falco over love letters she had written to one of her former college teachers. She paid Falco's initial monetary demands, but then refused when he kept demanding more money. Angered, Falco kidnapped Martha. Desperate to help Martha, with whom he had fallen in love, Dane had a breakthrough in his scientific research. After imbibing a formula he had developed, he discovered that with intense concentration, he could drastically decrease his size while still maintaining his strength as though he were at full size. Dane willed himself to shrink to the height of six inches, but with his normal strength intact. Dane used his new-found power to take down Falco and rescue Martha. Afterwards, Dane decided to fight crime as the diminutive Doll Man. He was often assisted by Martha, who became his scientific research assistant and his wife.
Several years later, when Doll Man was in trouble, Martha desperately wished she had the same ability to shrink in order to aid her husband. At that moment Doll Man wished the same thing, and suddenly Martha's height and weight dwindled down until she was on the same scale as Doll Man. She rescued Doll Man, and then regularly teamed with him as Doll Girl.
Doll Girl is a Quality Comics character who dates back to the Golden Age. She was created by Chic Stone, Jerry Iger, and Will Eisner, the same team who created Doll Man. She made her first appearance as Martha Roberts in Feature Comics #27 (1939), but did not appear as Doll Girl until 12 years later, in Doll Man #37.
Quality Comics went defunct in the 1950's, and Doll Man and Doll Girl left the public eye for many years. In the 1970's, DC Comics bought the publishing rights to the Golden Age Quality Comics characters, and both Doll Man and Doll Girl became the property of DC Comics. Doll Man became a founding member of the Freedom Fighters, a super-team made up of former Quality Comics characters, but Doll Girl did not appear. Later, when the Freedom Fighters moved from Earth-X to Earth-1, it was revealed that Martha Roberts had died of cancer back on Earth-X.
On Earth-1, Doll Man encountered the Earth-1 version of Martha Roberts. This Martha Roberts was a reporter who had never gained Doll Girl powers. After the Crisis on Infinite Earths, which merged all of the different DC realities into one reality, the two versions of Martha Roberts were merged as well. She once again had Doll Girl powers and was Doll Man's wife and crime fighting partner, as well as a reporter. But the merged version of her character was rarely seen, making brief appearances in only 2 issues.
In 2006, DC completely rebooted the Freedom Fighters and all of the characters who made up the team. Doll Man was now permanently stuck in a miniaturized state. In a repeat of previous history, Doll Girl did not appear, and it was revealed in 2008 that she had died of cancer once again. Like Doll Man, she had become permanently stuck at miniaturized size, and at that size could not receive the medical treatment she needed.
The DC Universe was rebooted again in 2011 with the advent of the New 52. A new version of Doll Man appeared and has teamed up with Jennifer Knight (the New 52 version of Phantom Lady, a longtime Freedom Fighters teammate). But Martha Roberts/Doll Girl has not yet been mentioned, so it is not yet known if she exists in New 52 reality.
Height: 5' 6," (as Doll Girl) 5-1/2"
Weight: 108 lbs, (as Doll Girl) 4 lbs
By willing herself to do so, Doll Girl could shrink to a height of five and half inches and proportionate weight. She could also will herself back to her normal size and weight. She retained her full-sized strength at doll size, effectively giving her super-strength while shrunk. As her crime fighting career continued, she developed into a good hand-to-hand combatant. Doll Girl wore a special costume that changed size as she did. Her costume was the same design as Doll Man's, only with the colors reversed (red outfit with blue accessories, while Doll Man wore a blue outfit with red accessories).