A newborn infant with a disorder of sexual differentiation

Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.

Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.

Development of the reproductive organs in an embryo starts from a bipotential state. This means the early embryo can develop either male or female reproductive organs. The formation of these organs begins with the growth of gonadal ridges that arise from the intermediate mesoderm during the fifth week of development.
Near the gonadal ridges, two duct systems are present: the mesonephric ducts (Wolffian ducts) and paramesonephric ducts (Müllerian ducts). These ducts form the basis for the male...

Sigmund Freud's psychosexual theory of development suggests that early childhood experiences significantly shape personality and behavior. Freud proposed that development is discontinuous, occurring in five distinct stages, each defined by a focus on different erogenous zones. He believed that failure to resolve the conflicts specific to each stage successfully could result in fixation, potentially influencing behavior as adults.
The Five Stages of Psychosexual Development
Freud's psychosexual...

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This produces daughter cells with abnormal chromosome numbers.  Nondisjunction is common during anaphase I or anaphase II of meiosis.  Mutations in synaptonemal complex proteins that attach homologous chromosomes increase the chances of nondisjunction in anaphase I of meiosis I. In contrast, mutations in topoisomerases and condensins that hold sister...

During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.