Sponges reproduce by both sexual and asexual means. They produce spermatozoa and ovocytes, but do not have reproductive organs. Fertilisation is difficult to observe. It may take place in seawater or in the mother sponge. In the latter case, the spermatozoa are carried to the mother sponge by currents of water. Embryonic development generally takes several weeks and results in swimming larvae. Sponges may be hermaphrodite (with a single individual producing both spermatozoa and ovocytes) or gonochoric (separate sexes).
Under certain conditions (on occasion, stress) sponges are capable of producing buds, which lead to a new sponge. This is asexual reproduction.
When cut or partially torn away (or nibbled), sponges are capable of forming scars and regenerating their lost parts. This property makes possible the practise of spongiculture.