Why do some kids look less like their parents than other kids do?
You can't always guess a child's appearance just by looking at his or her parents. The study of genes-called genetics-is achieving breakthrough all the time, but much about heredity remains mysterious.
Combination of genes can affect other genes, leading to unpredictable characteristics or features that lurk in the genetic background for several generations.
Our genes are also riddled with so-called junk DNA that doesn't seem to express itself in any noticeable way. Environment and diet also play a large role in shaping a person's weight, skin tone, and other physical characteristics.