Final answer:
Before 8 weeks of development, the sexual anatomy of male and female embryos is the same, which is true. Distinct male or female reproductive organs develop only after the 8th week, around weeks 9 to 12 of fetal development.
Step-by-step explanation:
The statement that before 8 weeks of development males and females have the same sexual anatomy is true. Early in development, all embryos have bipotential gonads that can differentiate into either male or female sex organs, and structures like the Müllerian and Wolffian ducts, which can develop into different reproductive structures depending on hormonal influences. It is the presence of the Y chromosome, and particularly genes on it like SRY, which cause the secretion of testosterone in males that leads to the development of male reproductive organs from these same tissues.
Differentiation of these tissues into distinctly male or female reproductive organs doesn't occur until approximately the 9th to 12th week of fetal development. Prior to this time, the external genitals are similar in appearance. After this period, especially by the end of the 12th week, external genitalia differentiate enough to assign a biological sex, often observed via ultrasound.
Therefore, the answer to the question is true; boys and girls cannot be distinguished based on their sexual anatomy before around 8 weeks, since differentiation occurs during the fetal period from weeks 9 to 12.