Dr. Nathaniel Essex ran an obstetrics clinic in New York in the late 19th century and performed side research on society's deviants. In to the 20th Century he took the alias Nathan Milbury a name off the name of the manor of his former wife, Sinister had unrestricted access to an abundance of generational genetic material to study, including that of the adult Daniel Summers, the first Summers in America and a former victim of his experiments in London, and his wife, Amanda Mueller.
Black Womb Project
In 1946, a Dr. Milbury and the clinic was involved with Project: Black Womb, a secret government project headed by Amanda Mueller and aided by Dr. Brian Xavier, Dr. Alexander Ryking, Dr. Kurt Marko, and Irene Adler, which studied, but did not alter, thousands of children, mostly mutants, in post-natal holding tanks. The project was based in Alamogordo, New Mexico. Dr. Milbury took samples from a young Charles Xavier and Carter Ryking. Other subjects were; Cain Marko, and Mortimer Toynbee among others.
State Home for Foundlings
As part of the clinic he opened the State Home for Foundlings, so as to experiment on the mutant genome. A couple of his subjects Scott Summers and his brother, Alex Summers were brought to the orphanage for study as they were descendants of Daniel Summers.