Which of the following statement regarding sexual differentiation of the fetus is TRUE?
The key to sexual dimorphism is the Y chromosome, which contains the testis determining gene called the SRY gene on its sho arm. The protein product of this gene is a transcription factor initiating a cascade of downstream genes that determine the fate of rudimentary sexual organs. The SRY protein is the testis determining factor; under its development occurs; in its absence, female development is established. Gonadal development is apparent from about 5 weeks of gestation as a thickened area of the urogenital ridge. The differentiation of the gonadal ridge into the testis by 43-50 days (7-8 wks) of gestation is a rapid phenomenon that contrasts with the slower and delayed development of the ovary, which will not become apparent until 140 days (20 weeks) of gestation with the formation of granular cells. Leydig cells are apparent by about 60 days and differentiation of the male external genitals occurs by 65-77 days of gestation. Ref: Langman's Embryology 10Ed Page 243-244; Moore's The Developing Human 7th Ed Page 304.
Gonadal development begins at 10th week of intrauterine life
Y chromosome determines the differentiation of ovaries
Female external genitalia development is completed by 10 weeks
SRY protein is the testis determining factor