Read the given passage and answer the following questions:

Spermatogenesis results in the formation of sperms that are transported by the male sex accessory ducts. A normal human sperm is composed of a head, neck, a middle piece and tail. The process of formation of mature female gametes is called oogenesis. The reproductive cycle of female primates is called menstrual cycle. Menstrual cycle starts only after attaining sexual maturation (puberty). During ovulation only one ovum is released per menstrual cycle. The cyclical changes in the ovary and the uterus during menstrual cycle are induced by changes in the levels of pituitary and ovarian hormones. After coitus, sperms are transported to the ampulla, where the sperm fertilises the ovum leading to formation of a diploid zygote. The presence of X or Y chromosome in the sperm determines the sex of the embryo. The zygote undergoes repeated mitotic division to form a blastocyst, which is implanted in the uterus resulting in pregnancy. After nine months of pregnancy, the fully developed foetus is ready for delivery. The process of childbirth is called parturition which is induced by a complex neuroendocrine mechanism involving cortisol, estrogens and oxytocin. Mammary glands differentiate during pregnancy and secrete milk after child-birth. The new-born baby is fed milk by the mother (lactation) during the initial few months of growth.

What determines the sex of the embryo?

X or Y chromosome in the sperm

The correct answer is Option (3) –X or Y chromosome in the sperm

The X or Y chromosome in the sperm determines the sex of the embryo.

• Sperm can carry either an X chromosome or a Y chromosome. If a sperm carrying an X chromosome fertilizes the ovum, the resulting embryo will be female (XX). If a sperm carrying a Y chromosome fertilizes the ovum, the embryo will be male (XY).
• The ovum always carries an X chromosome, so it is the sperm that decides whether the embryo will be male or female.
• Ovarian hormones do not determine the sex of the embryo; they regulate reproductive processes like ovulation and menstruation.
• The zygote's division is a part of early development, but it does not influence the genetic sex determination.

Thus, it is the X or Y chromosome in the sperm that determines the embryo's sex.