Tom is an expactant father who is worried that he will pass on his Haemophilia A, an X linked recessive disease, to his offspring. The mother is homozygous dominant. Explain why his 1st generation offspring will not be affected by the condition.

A recessive inheritance pattern means that 2 copies of the mutant allele need to be inherited for the individual to be affected. The disease is X linked, meaning the allele is only found on the X chromosome. So a male only needs one copy of this allele to be affected.If Tom's offspring is male then he won't be affected as he would have inherited the Y chromosome from his father, not the X chromosome so he isn't even a carrier.If Tom's offspring is female then she also won't be affected becuase she only has one copy of this allele, so she is just a carrier.