div class=ts-pagebutton class=gotoPage data-page=1Page 1button div class=ts-imageimg data-url=embryo-research-579c3c2e23c8chtmlpage=1 data-page=1 class=ts-thumb lazyload alt=Page 1: Embryo research loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAQAAADYv8WvAAAAD0lEQVR42mP8X8AwAgiABKBAv+vAXklAAAAAElFTkSuQmCC data-src=https:reader031vdocumentssitereader031viewer2022020523575068711a28ab0f07b02d13html5thumbnails1jpg width=140 height=200 divp© Nature Publishing Group1985pdiv