I consulted with Jenny Chen, a graduate student who studies genetics at MIT. Her predictions are based on general trends scientists have noticed in studying the genetics of facial features. According to her, nothing definitive can be made about the future appearance of the daughter and son. However, some traits are more likely to appear than others…
The child has a 50% chance of having green eyes (like Kate) and 50% chance of having blue eyes (like Will). So, in the illustrations, the daughter has blue eyes and the son has blue eyes Almond eyes tend to be dominant over round eyes. Kate has almond eyes, so it’s a good bet that her children will have almond eyes.
Kate’s olive skin colour is dominant over the lighter skin of Price William, so there’s a strong chance the child will have Kate’s skin type.
Kate’s dark hair is dominant over William’s light hair, so the children will likely have dark brown hair like Kate.
William and Kate do not have widow’s peaks, so their child will not have this trait.
Kate has dimples, which is a dominant trait. So it’s likely that her dimples will be passed down to her children.
Kate and Will have free earlobes, which is a dominant trait. So it’s likely their kids will have this trait.
Because broad lips are dominant over thin lips, and because broad lips seem to have a history of the Royal Family, it’s likely that the children will have broad lips.
Because both Will and Kate have oval faces, and because oval faces are dominant over square shaped faces, it’s likely that their kids will have oval shaped faces.
Heart-shaped faces tend to be a characteristic of female faces, so Kate’s daughters will probably take after her heart-shaped face while her sons will have jawlines more similar to Will.
If you look at Prince Philips, Prince Charles, and Prince Williams and Prince Harry, you will notice that they all have a very distinct nose shape that is flat at the bridge and a bit hook-shaped. This would suggest that this nose shaped is very dominant and that Will’s kids are likely to have this nose shape, also.