Through sexing, biologists and agricultural workers determine the sex of livestock and other animals they work with. The specialized trade of chicken sexing has a particular importance in the poultry industry.
Assisted physical sexing is a relevant issue in vertebrates with cloaca (e.g. birds, reptiles or amphibians) when there are no external sexual dimorphism. In veterinary practice, fibroscopy is used under general anaesthesia in birds such as parrots. Molecular sexing are techniques using DNA for determine genders in wild (population studies) or domestic species (farming, genetics) or man (archaeology, forensic medicine). Markers commonly used include: amelogenin, SRY, and ZFX/ZFY. Various techniques have been developed using simple polymerase chain reaction product size dimorphism, presence/absence, restriction dimorphism, or even sequencing.