To conceive a baby, couples need to have sexual intercourse on the woman's fertile days of her menstrual cycle. To help you work out your fertile days, try our Ovulation Calculator, which will tell you when you are releasing an egg each month, or ovulating. Ovulation can also be detected by using a combination of physical observations, including counting the days of your menstrual cycle, taking your temperature and/or looking for specific physical signs. You can learn more about conception here.