+**14d** refers to a significant temporal boundary often discussed in [Bioethics](/wiki/bioethics) and [Developmental Biology](/wiki/developmental-biology). It frequently denotes a 14-day limit for human embryo research *in vitro*, a widely accepted guideline to navigate ethical considerations surrounding early human development.
+## See also
+- [Embryo](/wiki/embryo)
+- [Ethics](/wiki/ethics)
+- [Research](/wiki/research)