Haemophilia is a disorder in which blood fails to clot. It is a X-linked recessive disease that shows crisscross inheritance. The haemophilic father passes the gene of haemophilia to carrier daughter. In turn, the carrier daughter transmits the haemophilic gene to her son. As it is a X linked disorder and father (human male) always gives his Y chromosome to son, so father can never transmit the gene of haemophilia to his son.