What did Queen Victoria always carry which was fatal to men?

The haemophilia gene.

Exactly so and there's supposedly a royal scandal. Some mischievous historian traced her ancestry and could find no history of any ancestor of hers being haemophiliac.It's a rare condition, the odds being something like 50,000 to 1 against the gene being carried.It's carried by females but the condition manifests itself in males.Either Victoria was exceptionally unfortunate or her ancestry was not quite what it's recorded as being

She herself transmitted it, in time, to all the royal families of Europe.

I remember that I asked a question about it a while ago.

I found it.

"In about 30% of cases of Hemopilia B...there is no family history of the disorder and the condition is the result of a spontaneous gene mutation" -- Wikip.

Sounds like Victoria may have been an innocent victim of the effect of cosmic rays on her parents.