When Phoebe pulls out the family tree and finds P. Russell, the dates are July 2, 1894- Feb. 17, 1924. She then states that the dates match up, as well as the age. This would make Phoebe 30 years old, which we know she is not. When she first finds her name, the date of birth is November 2, 1975. This makes Phoebe 24 at the time of the episode.
Leo states that he and Piper are former lovers from in and around the roaring '20s. It is also established that "Leo" died during World War II. Leo was in his twenties when he died in World War II so the "Leo" incarnation of his soul would have already been born in the 20s, thus he could not have been Piper's lover at that time as Leo was already alive as a young boy. Both incarnations could not be alive at the same time.
The family tree lists Patricia's birth as 1950. But in "Witchstock"(6:11) Grams' husband Allen/Jack says he took "the baby" to his sister's. The "baby" would have been either 14 or 17 years old when her father died depending on which version you accept (1964 family tree, or 1967 the real Summer of Love in S.F.). And Penny, according to the family tree, would have been 13 years old when she gave birth to the girls' mother Patricia.