If the offspring Is male the father passes on Y chromosome. If the trait is recessive and carried on the X chromosome then because the males only have one X chromosome the trait will be expressed, this is why they have a much higher chance of inheriting the trait, whereas if it was a female who inherited the recessive trait the other X chromosome she has can provide genes that are damaged or missing. E.g. Haemophilia Red-green colour blindness Duchenne muscular dystrophy
