Calmens - Fertility Calendar Software - Windows Shareware $15. Calmens is a software application, which helps you to plan the gender of your future child, calculate the fertile days (if you intend to get pregnant), calculate the most probable days to conceive a girl or a boy, calculate the approximate day of the baby's birth, calculate the zodiacal sign of your baby, calculate the safe days for unprotected sexual intercourse, calculate the day of the next menstruations.