Final answer:
People with a 47,XY karyotype usually develop as male due to the functioning SRY gene on the Y chromosome. However, if there's no SRY gene or it's not working, they will phenotypically develop as female. There are exceptions because chromosomal disorders can uniquely impact sexual development.
Step-by-step explanation:
In understanding human sex determination, the presence of the SRY gene on the Y chromosome plays a critical role. If the SRY gene (Sex-determining Region of the Y chromosome) is present and functional, it triggers the development of male sex characteristics. However, whether the individual's karyotype is 47,XY or not, the absence or dysfunction of the SRY gene leads to them developing as female, a condition known as Swyer syndrome. This happens because, without the SRY gene prompting the development of male sex characteristics, the individual remains phenotypically female, which is considered the 'default' developmental pathway.
Conversely, with a functioning SRY gene, even a 47, XY karyotype individual will express male phenotypic characteristics. However, it's important to note that other chromosomal disorders may affect sexual development, regardless of the SRY gene's presence, leading to conditions such as Turner syndrome or Klinefelter syndrome.
Learn more about Sex Determination