sentences:  In 2007, a patent application was filed on methods for creating human female sperm using artificial or natural Y chromosomes and testicular transplantation.Key to successful creation of female sperm (and male eggs) will be inducing male epigenetic markings for female cells that initially have female markings, with techniques for doing so disclosed in the patent application.In 2018 Chinese research scientists produced 29 viable mice offspring from two female mother mice by creating sperm-like structures from haploid embryonic stem cells using gene editing to alter imprinted regions of DNA.