Someone here said that Queen Victoria was half German. She was almost all German if one considers her genetic background. Her father the Duke of Kent was the son of two Germans, if I remember correctly (I am speaking of genes here, not place of birth). Her mother was a cousin of the Duke of Kent specifically imported from Germany to provide a suitable mother for the Duke's desired heir. We would have to look back a few generations to find anything but German here.
The Duke of Kent's mistress, who went by the name of Julie, was of French and Italian descent, and would have brought more genetic variation into the family. They supposedly had at least one child (some say more than one) but this information, I have read, was concealed by Victoria herself, when she came to the throne. I my readings about Edward Duke of Kent and Julie, some sources say the knowledge about their children was concealed. Others say that their descendants were known. One story is that their son Robert Woods married Charlotte Grey, the daughter of a parliamentarian known as "Earl Grey", for whom the tea was named. In fact, when searching their heredity at a Mormon genealogical site, I found the marriage of Robert Woods and Charlotte Grey, the daughter of Earl Grey. As I recall, they had several children, but Robert died young. I did not follow that line further.
This isn't exactly accurate.
While the Duke and Duchess of Kent were likely related (I can't remember how closely), they weren't cousins. Going back 3 generations there isn't a single common ancestor (in comparison, the QEII and the DoE have their first common ancestor in Christian IX at 3 generations back for both of them, and their second in Victoria at 3 generations back for HM and 4 for the DoE).
While all of the Duchess of Kent's recent ancestors were German (she was, after all, from Germany), you kind of have to question at what point a family ceases to be of whatever nationality their ancestors came from and of whatever nationality they're raised to be. Victoria was born on British soil. She was raised there, spent the vast majority of her life there, and eventually died there. Her father, likewise, was born, raised, and died on British soil, although he travelled and lived elsewhere more than his daughter. The Duke of Kent had a German mother, but his father, GIII, was also born, raised in, and died in Britain. GIII's parents were both born in Germany, and you can follow the paternal line there back a bit (Frederick, PoW, GII, and GI), but GI's mother was Sophia of Hanover, whose mother was born in Scotland. If we argue that Victoria was German because her great-grandfather was born in Germany, then by that extension Sophia was Scottish because her mother was born in Scotland (and in turn, her son, GI, and grandson, GII, were also Scottish, or British...).
As for the Duke of Kent's alleged child... This is a myth. The Duke of Kent was with Julie from 1790 to 1818. Any child they had would have been covered up long before Victoria came to the throne - Victoria did not have the power to completely destiny evidence of the existence of a child born a minimum of 19 years before she came to the throne (and that's assuming that the then 58 year old Julie had given birth to a child the year she and the Duke split up). If a child was born and a cover up happened then it was the Duke and Julie who did it, as they would have given up the child for adoption - there are claims that Robert Woods is a child who was born to them while in Canada and then adopted by an aid and left behind when the Duke left Canada. However, as the Duke's brothers made no attempt to hide their illegitimate children born around this time I can't see why he would have either. Instead the whole "I'm descended from the illicit relationship between a Prince and his mistress who had a secret baby" story seems to be more of a fantasy some families have made up for their geneologies.
As for a marriage between Robert Woods and a daughter of Earl Grey, neither Wikipedia nor The Peerage list a daughter named Charlotte as having been born to Charles Grey, 2nd Earl Grey (the parliamentarian for whom the tea is named). In fact, none of the Earls Grey are listed as having a daughter named Charlotte. The 2nd Earl did have a daughter, Mary, who married one Charles Wood, 1st Viscount Halifax of Monk Bretton though.
I was having a general think about why royals marry non royals and it occurred to me that as young adults, their entire circle of friends is confined to those that played in the same sandbox, went to the same schools, socialised with throughout their lives. 
