Thursday, December 14, 2017

Boy or Girl? Depends On The Father's Genes

In a study by Newcastle University, thousands of families were used to study their family trees and see what the expecting parents would likely have. The purpose of the study was to show that whether a couple would have a boy or girl solely depends on the fathers genes. The sex of the baby is believed to be inherited so if a man has more brothers then he is expect to have sons, and the same goes for if he has more sisters it would be expected that there would be more daughters. The study suggests that a undiscovered gene controls whether a man's sperm has more X or Y chromosomes. The study also suggests that the gene consists of two alleles that result in three possible combinations; one being mm and results in the man producing more Y sperm and having more sons, the other being ff and results in the man producing more X sperm and having more daughters, and the third combination mf results in the man being equally likely to produce X sperm as he is to produce Y sperm. The picture above shows how the grandparents affect their children and grandchildren.

This is very interesting to read. I feel like more people should know about this because a lot of times people just wish they could have a daughter or wish they could have a son. If people read this article and created a family tree even without much genetic knowledge they can have a better idea of what they're likely to have.


  1. Reading this post I found this to very interesting because it is something like in comparison to when after the war women would have more boys than girls because their testosterone levels were high. Reading this article reminded me of that. I agree with you that people should know about when planning to have a child they will have a better genetic knowledge of what they are likely to have

  2. This research is very interesting! We actually talked about this in genetics lab this semester. Theoretically, having 6 boys in a row would indicate that it would not be due to random chance, and there would be something biologically wrong which inhibits a woman to have a female. It clearly makes sense that the father would be responsible for a couple being incapable of having a girl because we already know that the mother gives her x chromosome, and the father gives his x or y chromosome, which in result determines the baby's sex. The ff and mm genotypes seem to be recessive, being that you need both alleles in order for the trait to be expressed, that is why it is uncommon for a couple to have only one sex. I also feel like once this gets to the public, couples are going to go to genetic councilors so they could increase their chances of having a male or female. But this is interesting! In response to Jasica's comment, I know a lot of people who firmly believe that is you withhold having intercourse for a longer period of time, you will increase your chances of having a male. This research definitely discredits that idea.