A twin female pregnancy was obtained in a haemophilia carrier after two preimplantation diagnosis cycles. The embryonic sex of biopsied blastomeres was determined with the use of dual fluorescence in-situ hybridization with directly labelled DNA probes specific for the X and Y chromosome. A twin female pregnancy was confirmed by means of ultrasonography and amniocentesis at the 14th week of amenorrhoea. The patient delivered two healthy females by Caesarian section at the 37th week of pregnancy.