Some of his early work led to stories about “an end to men”, enabling lesbian couples to have their own biological children without male involvement but, according to Prof Nayernia, these were based on a “misunderstanding”.
“IVD sperm can only be produced from stem cells with male [XY] chromosomes,” he said. “Stem cells with female [XX] chromosomes can be prompted to form early-stage sperm but do not progress further. This demonstrates that the genes on a Y chromosome are essential for meiosis and sperm maturation.”
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