Question:

A close friend confides in you that he thinks that one of "his" children is not his.  When pressed for details he points out to you that both he and his wife have dark brown hair and that his baby has blonde hair.  In the conversation he adds that although his mother was a blonde and his wife's father was a blonde, that it is pretty obvious that neither he nor his wife have blonde genes.  What do say to your friend?  Use a chart or diagram to support your conclusions.

Answer:

In talking with my friend who has confided in me about his children not being “his” due to a difference in hair color, I first and foremost would try to calm his worries and explain to him to not go through his marriage thinking his wife is unfaithful. Explaining to him if it were me in his wife’s place and he came to me with that accusation, I would be extremely upset and put off. 

Secondly, I would attempt to explain and inform him of the factors of why his young kids could have blonde hair. Though he already has members of his family that have blonde hair doesn’t mean that there are not chances that “his” children would not follow by those “family genes”. Further detailing that from the time the kids were created after conception, in their little baby cell or “zygote,” is the beginning of the connection that determines the outcome of the baby. Stating that information from scientific research has proven that we receive 46 total chromosomes from our parents at birth, so 23 from mom and 23 from dad and within those variations of chromosomes can come with 8 million versions from each parent (2.1, Invitation to The Life Span, 4e, pg. 45). Making him understand the chances of having “exact” replicas of themselves (himself and his wife) is totally possible but there is also a very large chance that they can have different outcomes as well. 

Leading with two possible examples like with eye color, if he and his wife have the same chromosome 15, like genes for brown eyes for instance, than the chance of their baby having brown eyes is possible. Their child would be deemed “homozygous”, because the traits of that 15 chromosome are mirrored exactly to each other. But that fact that if there is a small difference in his genetic code or his wife’s, could mean that their baby could come out with a color different from just brown. 

Honestly in my experience when trying to explain medical terminology, surgical processes, or what I have learned from class to friends or family they often give me blank stares, act like they understand, or seem a little puzzled. But because this is my friend and he seems seriously concerned if he didn’t fully understand my first explanation, I would then follow through with a diagram.

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Explaining that him and his wife may be carriers of a blonde hair gene. Telling him that to be a carrier is defined as, “A person whose genotype includes a gene that is not expressed in the phenotype...”  (2.1, Invitation to The Life Span, 4e, pg.53).  Though he and his wife both have brown hair, they still carry what is known as a “non-recessive” gene to which in his and her family could be the blonde hair type. That they have a 1 in 4 chance, like the baby above in the diagram to come out with a different color “eye” or “hair color” like his family. Maybe they really got the blonde hair from grandma or grandpa, or great grandma or great grandpa, etc. The fact of the matter is that someone in the family had the gene and it was carried through them (himself or his wife).

In final, I would tell him that his worries/distractions of whether his children are his or not because of something as simple as their hair color is simply nothing to worry about. Everyone comes from a long line of many family members before them that gave various options of what they could look like today and in the future.

Reference:
Berger, K. S. (2019). Invitation to the Life Span, 4th Ed. New York, NY. Worth Publishers.

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Picture:
Berger, K. S. (2019). Invitation to the Life Span, 4th Ed. New York, NY. Worth Publishers.