Yes, baby gender is determined genetically. The father's sperm carries either an X or a Y chromosome. The mother always contributes an X chromosome. Therefore, the father's contribution determines the sex of the child:
- XX: Results in a female child.
- XY: Results in a male child.
This fundamental biological process is well-established, as evidenced by numerous scientific sources. While there's a slight bias toward male births in some populations (as noted in the UT Southwestern Medical Center blog post), the underlying mechanism remains consistent: the sex chromosomes provided by the father's sperm determine the sex of the baby. Several studies, including the Newcastle University research referenced, have explored the genetic influences on sex ratios, but the basic principle of X and Y chromosome determination remains unchallenged. Modern genetic testing methods, like those mentioned in the Cleveland Clinic article on pregnancy genetic testing, can even determine the fetal sex early in pregnancy.
While some sources discuss potential genetic influences on the probability of having a boy or a girl (e.g., family history suggesting a predisposition), the mechanism itself is purely based on the genetic material contributed by the father's sperm: an X chromosome for a girl and a Y chromosome for a boy. This is explicitly stated in multiple sources such as ScienceDaily and the Newcastle University press release. The Reddit posts, while mentioning family trends, further support the core principle of chromosomal determination.
