Whether your baby will have blue eyes, green eyes, or any other combination depends mostly on the parents eye color and background.
Believe it or not, a baby can have blue eyes if both parents have brown eyes. Eye color is determined by the parents' eye color and whether the parents' genes are dominant genes or recessive genes. Brown and maybe green are considered dominant, but even two browns can make a blue-eyed baby, because there are no full 100 percent definite rules, so you can only go by a percent.
If both of you have brown eyes, then there is generally a 25% chance that the baby will have blue eyes if both of you carry the recessive blue-eye gene. But if only one of you has a recessive blue-eye gene, and the other has two brown, dominant genes, then there is a less than 1% chance of the baby having blue eyes.