existence overlaps existence starts during or after produced_by produced by gamete PMID:28434803 PMID:20844018 https://orcid.org/0000-0003-2569-1939 | https://orcid.org/0000-0002-7535-4611 PMID:27149082 PMID:27304889 A mature sexual reproductive cell having a single set of unpaired chromosomes. Planarian_Anatomy PMID:23652002 PMID:27163480 CL:0000300 juvenile reproductive system product gonad germ cell adult hermaphrodite