Haemophilia is a X-linked recessive blood disorder. In it, the individual has delayed clotting time for blood which can be fatal. X-lined disorders are inherent disorders due to mutation in the X-chromosome which causes the phenotype to be always expressed in male and in female only in homozygous condition. For a daughter to be haemophilic, her father must be haemophilic as she receives one X-chromosome from him. And mother must be a carrier if not haemophilic to pass the X- chromosome to daughter.