Most species require some form of conditioning prior to breeding such as seasonal changes in day-length or temperature. However many lizards will become reproductively active even if kept in isolation which can often result in anorexia, debilitation and egg retention. Many female lizards die as a consequence and therefore very serious consideration should be given to routine neutering of the larger pet lizards, especially the iguanas, bearded dragons, water dragons etc.
Most lizards lay leathery (e.g. green iguana) or calcified eggs (e.g. many geckos) but some are live bearers (e.g. blue-tongued skinks). Leopard geckos and bearded dragons will lay eggs in damp vermiculite (for example, in the humidity chamber) and these can be artificially incubated; for example, leopard gecko eggs will hatch after 6-12 weeks if incubated at 28 - 32ºC, with more males produced at the higher temperature and more females produced at the lower temperature.