Gametophytes produce gametes, which are specialized reproductive cells.

Here's a breakdown:

* Gametophytes are haploid (containing only one set of chromosomes) multicellular structures that develop from spores.

* Gametes are haploid cells, specifically sperm and egg cells in sexually reproducing organisms.

* Fertilization occurs when a sperm cell and an egg cell fuse to form a diploid zygote, which develops into a new sporophyte.

This is part of the alternation of generations life cycle, which is common in plants and some algae.