A Hemophiliac is someone who, when bleeding will find it incredibly difficult to stop the blood flow. Basically the coagulants that would normally clot the blood and seal the wound don't function, or don't exist like they should. Its a serious problem since even a small cut can be very serious, and falling over could cause Bad internal bleeding.
No, Queen Victoria's husband Prince Albert was not a hemophiliac. Hemophilia is a sex linked gene carried on the X Chromosome. If Prince Albert had been a hemophiliac than his sons could not of had hemophilia and all of his daughters would have been carriers. This was not the case however. One of Victoria and Albert's sons had hemophilia and two of their daughters passed the gene on. This means that it was Queen Victoria herself that passed it on, not Albert.
Alexei was Czar Nicholas' youngest child and only son. Unfortunately for the succession of the throne, Alexei was a hemophilliac, meaning his blood barely clotted. A paper cut that's just annoying for the average person could have put Alexei in a hospital ICU. His illness is what brought Grigorii Rasputin, who claimed he was a healer, into the royal court. Alexei was assasinated along with his family in the 1920s after the civil war.
Had he not been forced to abdicate, his only son Alexei would have become czar eventually. However, Alexei was a hemophilliac, meaning his blood had a hard time clotting. A single pinprick could cause him to bleed out. Had he died before his father and Nicholas had not had another son, the czar eldest daughter Olga would become the Czarina.