If both parents have blue eyes, the odds of their baby having blue eyes is 100 percent. If both parents have brown eyes but possess one copy of the blue-eyed gene, the odds of their offspring having blue eyes is one in four.
According to Science Daily, the allele, or version of the gene, for blue eyes is recessive to the allele for brown eyes. Therefore, for a person to have blue eyes, that person must have two copies of the blue-eyed allele. This means that people who lack the blue-eyed gene cannot produce blue-eyed children unless there is a genetic mutation.