Mechakko Dotakon (1981)

Geeky genius Michiru has already got her Ph.D. in atomic physics (from California university) by the age of 11. But she still longs for a little brother, so she builds her own. Robot boy Dotakon is soon joined by their little robot sister, Chopiko, and the trio embarks on a series of fantastic adventures fueled by Michiru's inventions.