The statement that "haemophilic females are never born" is not entirely accurate. Hemophilia is a genetic disorder that affects the blood's ability to clot properly, and it is primarily an X-linked recessive disorder. This means that the gene responsible for hemophilia is located on the X chromosome.
Females typically have two X chromosomes (XX) and males have one X and one Y chromosome (XY). If a male inherits an X chromosome with the hemophilia gene from his carrier mother, he will have hemophilia because he only has one X chromosome, and the Y chromosome does not carry a corresponding healthy gene to compensate.
Females, on the other hand, have two X chromosomes. If one of the X chromosomes carries the hemophilia gene, the other X chromosome can often compensate for the faulty gene by providing the necessary clotting factors. As a result, female carriers of the hemophilia gene usually do not have symptoms of the disorder, or they may experience milder symptoms. In some rare cases, though, females with two affected X chromosomes (rarely due to non-disjunction during gamete formation) can have severe hemophilia.
However, it is essential to clarify that while females may not typically show severe hemophilia symptoms, they can still carry the gene and pass it on to their children. This is why it is crucial for carriers or individuals with a family history of hemophilia to seek genetic counseling before planning to have children, as there is a risk of passing the disorder to their offspring, regardless of the child's sex. With advancements in medical knowledge and technology, it is also possible to diagnose and manage hemophilia in both males and females effectively.