Allogamy the process of cross-fertilizing. It is a terminology utilised in the field of biological reproduction describing the fertilization of an ovum from one individual with the spermatozoa of another. The transfer of pollen grains from the anther of a flower on one plant to the stigma of a flower on another plant of the same species is called allogamy. Allogamy is the common form of out-breeding. It leads to heterozygosity. Such species develop heterozygous balance and exhibit vital inbreeding depression on selfing.