He took a degree in Medicine and Surgery at Santiago de Compostela University in 1973. In 1976, he specialised in Obstetrics and Gynaecology at Santiago University, after finishing his formation as resident doctor in the Obstetrics and Gynaecology Department at 'Xeral de Galicia' Hospital in Santiago de Compostela in 1974, 1975 and 1976. It was also in that year that he got a diploma at the School of Obstetrics and Gynaecology (Santiago de Compostela) that empowered him to practise this speciality. On 17th May 1977, he took over a post as assistant doctor in Obstetrics and Gynaecology at the so-called 'Hermanos Pedrosa Posada' Hospital in Lugo (today 'Xeral-Calde' Hospital). He got the 'Venia Docendi', granted by the rector of Santiago University to practise Teaching at the Nursing School in Lugo. He was responsible for the subject 'Maternal Nursing' during the courses 1979-80, 1983-84 and 1984-85. He was granted again the 'Venia Docendi' to practise Teaching during the course 1985-86 at 'Hermanos Pedrosa Posada' Hospital in Lugo.
He was on the board of directors of the Galician Society of Obstetrics and Gynaecology during the session that ended up in October 1994. From 1998 until his death, he was the head of the Obstetrics and Gynaecology section at 'Xeral-Calde' Hospital. He took part in the First International Symposium about Prenatal Diagnosis of Congenital Malformations, presenting the paper Atresia de Yeyuno (Madrid, April 1982). He collaborated as lecturer in the course Perfeccionamiento de Aspectos Actuales y preventivos en Obstetricia y Ginecología that took place at the Nursing School (Santiago de Compostela, 1984). He participated as Professor in the course about Maternal Education (Educación Maternal) at the Nursing School in Santiago de Compostela (December, 1986). He also collaborated in the work La Utilidad de nuestros Citodiagnósticos en la Identificación Microbiológica, published in the magazine 'Revista Galicia Clínica' (October, 1976) and in Protocolos Asistenciales en Obstetricia y Ginecología, published by the Spanish Society of Gynaecology and Obstetrics.
Gerardo Iglesias also attended many courses and conferences such as Curso de Ampliación de Fisiopatología y Patología Obstétrica (Faculty of Medicine, Santiago de Compostela, 1973), II Curso Internacional de Diagnóstico Ultrasónico en Obstetricia y Ginecología (Faculty of Medicine, Santiago de Compostela, 1975), II Curso de Citología Obstétrico- Ginecológica (Faculty of Medicine, Santiago de Compostela, 1975), III Simposium Internacional de Perinatología y Desarrollo Humano (Faculty of Medicine, Santiago de Compostela, 1976), XV Simposium Internacional de Patología Mamaria ('Dexeus' Institute, Barcelona, 1988), I Certamen Nacional de Vídeo en Obstetricia y Ginecología, taking part in the organising committee (Lugo, 1989), IV Curso Internacional Avances-90 en Gineco-Obstetricia y Reproducción Humana (Hospital General de Cataluña, 1990), II Certamen Nacional de Vídeo en Obstetricia y Ginecología, taking part in the organising committee (Lugo, 1990), III Certamen Nacional de Vídeo en Obstetricia y Ginecología, taking part in the organising committee (Lugo, 1992), VI Congreso Nacional de la Asociación Española de diagnóstico prenatal (Santander, 1993), IV Certamen Nacional de Vídeo en Obstetricia y Ginecología, taking part in the organising committee (Lugo, 1994), XXIII Simposium Internacional Mastología: Cáncer de Mama (Institut Universitari Dexeus, Barcelona, 1996) and V Certamen Nacional de Vídeo en Obstetricia y Ginecología (Lugo, 1997).