Abstract: In a clock, a device for planning the sex of a child according to the time selection method exhibits differently marked display sections (3, 4 and 5), relative to a display starting position (2), for labeling the days of fertility and the days of infertility in a cycle and a limited cycle variation range. Within the display section for the days of fertility (4), clearly distinguishably marked day position fields (G and B) are provided which, for cycle lengths of 27 to 30 days, serve as an indication of the days of probability for conceiving a boy or a girl. The counting and display of the days of probability by the cycle pointer (1) occurs from the respective first day of a new menstruation. Correspondingly, the display element (1, 11) can be adjusted to the starting position (2).