What are the haploid cells that form in female animals?

The haploid cells or sex cells are one of the foundations of life ,they have one part of each chromoson in your body,.But when two cells of opposite mating types meet they fuse to form a new live chromoson.In animals they are in the lower uterus ,as the aniamals stomache has no linning.When she becomes pregant ,the genes and amino acidsstart forming a sac in her stomach and haploid celss are drawn their ,by chromosons