Eye Color and Paternity Testing: a History
Determining paternity from eye color dates back to the 19th century. Based on the work of Gregor Mendel (1866), scientists began unlocking the secrets of inherited traits. Theories about genes and human development eventually led great minds like Watson and Crick to unravel DNA as a double helix model (1953), paving the way for modern geneticists to sequence the entire human genome in 2001.
Inherited Trait Theory
Mendel noted that dominant genes masked recessive ones; plants (or other organisms) with both dominant and recessive genes always showed the physical characteristics of the dominant gene. In time, scientists identified human traits linked to dominant and recessive genes such as ear lobe separation, blood type, and eye color.
Eye color follows a polygenic inheritance pattern, meaning that eye color is determined by more than one gene (probably by 6 or more genes). Generally, these genes express themselves as one of 8 different eye color types ranging from “light-blue” to “dark-brown” (which can appear nearly black in color). The dominant genes make the eye color darker; the more dominant genes present, the darker eye color appears.
Eye Color and Paternity Questions
Because eye color is linked to dominant and recessive genes, eye color can provide some clues about paternity. An "eye color paternity test” assumes that lighter-eyed parents (with recessive genes) cannot have darker-eyed children (who must have dominant genes).
2 'blue' eyed parents can have a 'Blue-green' (or lighter) eyed child, but not hazel or anything darker.
2 'dark brown or black' eyed parents can have a child with any of the possible eye colors (but it is unlikely they will have a light eyed child, such as light blue or blue).
1 'light brown' eyed parent and 1 'blue-green' eyed parent can have a child with any of the possible eye colors.
Problems with the Eye Color Paternity Test
Eye color cannot reliably answer paternity questions. Science is still working to better understand how multiple genes truly affect eye color—and whether other genes and other traits, such as skin color or hair color, might also be linked with eye color. Though unlikely, lighter-eyed parents sometimes do have darker-eyed children—even when a DNA test proves paternity.
Eye color cannot be determined accurately just by looking. What appears “blue” or “blue-green” to one may appear to another as “light-blue” or “hazel”—especially in different light. Eye color often appears much lighter at birth and may darken to its true color within 1 to 2 years.
Thus, eye color cannot reliably predict paternity. While an eye color paternity test may offer some clues about paternity, it is not consistent enough for definitive paternity test results. An IDENTIGENE DNA Paternity Test, now available at your local drug store, provides 2-day results. IDENTIGENE guarantees 100% accurate testresults because we run every excluded test twice.
If you have any questions about the iDaddy App or Paternity Testing, please contact us (Monday through Friday, 8 AM to 9 PM, ET).