There is no way to guarantee your chances of having a child in Stardew Valley. However, there are a few things you can do to increase your chances of having a baby:1) Get married and have a child2) Have romantic dates with your spouse3) Spend time with your spouse at the farm4) Give your spouse gifts and special meals5) Take paternity leave when your child is born6) Try to conceive after a year of marriage7) Go fishing together every Tuesday at 8pm.