A number of researchers have accepted the theory proposed that Peter was the son of a Jacob Rush and that Peter was twice married. His first marriage to Mary Cowell produced Isaac and Bethuel. His second marriage to Elizabeth Stull produced Charles, Paul, Phoebe and others. This is inaccurate.
The Peter Rush who married Elizabeth Stull and fathered Phoebe, Paul, Charles, etc., is the Peter in Monroe County in 1820. He could not be the father of Isaac as Isaac was born in 1785 and Peter was born between 1775-1794. Peter Rush who married Mary Cowel is not his father either as this family has been documented and resided in Cuyahoga County, Ohio.
The oldest Rush in census records is Jacob Rush (b 1740-1750) and wife Prudance (as recorded in Monroe County land deed).
Their proven children are:
1. Mary b 1784 w/o Alexander Massie
2. Samuel (in Indiana in 1833)
3. Margaret w/o David Culbertson, born 1774 in Bedford County, PA.
The following two have not been documented, but there is enough evidence to connect them as sons of Jacob.
4. Jeremiah b 1770-1780.
5. Bethuel 1791-1852
At one point, I believed that Isaac and Peter may have been sons of Jacob, but that theory has been discredited.