Intersex reproduction is not heterogamy.
Heterogamy is one of the forms of sexual reproduction and is relatively primitive. There are two types of heterogamy: physiological heterogamy, in which only gametes of different mating types can unite with each other, but there is no difference in the morphology of the gametes. There is also morphological heterogamy, in which the gametes involved in the union are different in size and sexual expression, but the shape is the same.
Heterogametic reproduction is generally found only in algae. In contrast, there is general hermaphroditism, represented by humans, in which the gametes of the two sexes differ greatly in shape, size, and structure, and are completely different from heterogametic reproduction.
Hermaphroditism is the union of gametes of both sexes in sexual reproduction. The phenomenon of reproduction with only one sex is called unisexual reproduction. Unisexual reproduction is in fact almost identical to parthenogenesis, but also includes egg mass development, etc.