At what week does the fingerprint start developing in a fetus?

The development of fingerprints in a fetus begins around the 14-week mark of gestation. During this period, the dermal papillae, which are the small bumps in the skin that form the patterns of fingerprints, start to develop. This process is crucial as the unique patterns of fingerprints are largely established by this time, influenced by genetic factors and the conditions within the uterus.

By the 14th week, the fetus also begins to exhibit more advanced skin development, including the formation of ridges that will eventually give rise to the distinctive patterns of fingerprints. This budding stage is essential for the future identification features seen at birth and throughout an individual's life.

The other choices fall outside this critical window for fingerprint development. By 12 weeks, the skin is still undergoing initial development stages without significant formation of fingerprint patterns, and at 16 weeks, while fingerprints begin to mature, the initial formation is indeed already underway by 14 weeks. Thus, 14 weeks is recognized as the key milestone when fingerprints start to take shape in the fetal development timeline.