Hi- congrats to your friend!! Although I have heard of this, I don't know of anyone who this has happened to.
I just googled this and found this website http://www.atlantadentist.com/baby_born_with_tooth.html.
Here's a quote:
A baby born with tooth is uncommon. Since it is so rare parents often worry a great deal about the tooth. A tooth that exists when a baby is born is called a neonatal tooth. Baby teeth begin forming when the baby is still in the womb. Sometimes the teeth just develop faster. Unless the tooth is loose it is not something you should really worry about too much although it is still a good idea to see a dentist to help determine what course of action should be taken.
In rare instances a baby born with tooth can actually have a spare tooth. That tooth that has already erupted, that the baby is born with, actually formed over the baby teeth that have yet to come in. The tooth is most often a bottom front tooth. If the tooth is an extra tooth it will fall out eventually when the real baby tooth is coming in but in some cases it may need to be removed. This will especially help with breast feeding the child.
I also just found a statistic that said one in 2,000 babies is born with one or more teeth.
Good luck to your friend!