So, is it a girl or a boy? This is the first question parents ask at the birth of an infant. Though the answer is obvious, the mechanism of sex determination is much less so. Researchers at the University of Geneva (UNIGE) attempt to shed light on this complex process by identifying the crucial role played by insulin and IGF1 and IGF2 growth factors, a family of hormones known for its role in metabolism and growth. In the absence of these factors at the time of sex determination, embryos do not differentiate into either male or female and have no adrenal glands. The results of this study, published in the journal PLOS Genetics, allow us to better understand sexual development and will eventually improve diagnosis and genetic counseling practices for individuals with disorders of sex development.
In mammals, sexual development is a long process beginning at conception when the sperm's transmission of an X or Y sex chromosome will determine the genetic sex of the embryo. The following developmental stages will translate this genetic sex into gonadal sex, that is, either ovaries or testes, which will secrete hormones that will masculinise or feminise the foetus.
The intention of the study conducted by Serge Nef, Professor at the Department of Genetic Medicine and Development at UNIGE, is to better understand the first stages of sexual development.
Growth, metabolism and reproduction