Early work in Scotland
The following year in 1928, Wiesner was appointed to the position of head of Sex Physiology by animal geneticist Francis Crew, Professor of Animal Genetics at the newly established Institute of Animal Genetics (IAG) established within the University of Edinburgh.
A number of notable scientists conducted research at the IAG, including physiologist John Scott Haldane, zoologist Lancelot Hogben and evolutionary biologist Julian Huxley. It was there that Wiesner built upon the work of Zondek and Aschheim by examining the production and role of hormones during fertilisation and pregnancy. Zondek and Aschheim had thought that the hormone chorionic gonadotrophin was produced by the pituitary gland. But the research conducted at the IAG proved that it is secreted by the placenta.
In 1929, Wiesner visited Montreal, where he discussed with some scientists the possibility of using medicine derived from female hormones to delay menopause. Later, the scientists helped form the company Ayerst, McKenna and Harrison, Ltd (later, Wyeth) who marketed Premarin, a controversial hormone replacement therapy (HRT) drug based on pregnant mare's urine.
He was awarded his ScD in genetics in 1930.