Meiosis is the division of gamete cells, which are sexual cells, rather than regular body cells (somatic cells.) There are two phases of meiosis, meiosis I and meiosis II, and each process has four steps: prophase, metaphase, anaphase, and telophase.  Meiosis begins with one diploid parent germ cell, containing 2 full pairs of chromosomes (46 chromosomes total) and results in the formation of four differing haploid cells which have 1 set of chromosomes (23 chromosomes total) each.

In males, meiosis and maturation results in spermatogenesis, which is the production of four sperm cells in the testes. In females, meiosis and maturation results in oogenesis, which is the production of ova or eggs (as oocyte turn into eggs) in the ovaries. During oogenesis, polar bodies  which are three nonfunctional products, are produced along with one viable ovum. During sexual reproduction, two haploid cells, one from the mother and one from the father, come together in fertilization, creating a diploid cell with 23 chromosomes coming from each parent.

Interphase

Like in mitosis, interphase occurs before any cell division occurs. Here DNA is replicated. 

Prophase I 

Prophase I follows interphase. During Prophase I,  chromosomes, which are long strands of DNA wrapped around histone proteins, are formed when chromatin, the nucleic-protein complex described above condenses, becoming shorter and fatter. These chromosomes make sister chromatids, which are 2 copies of the same chromosomes held together by a kinetochore structure. Prophase I is the longest stage in meiosis and takes up the most amount of time. 

Also in prophase I, the nuclear envelope starts to break down and spindle fibers start to form. 

Homologous chromosomes come together in this prophase I. Homologous chromosomes are members of a pair of chromosomes that are alike. They loosely pair up according to size, shape, genetic information, and the location of their centromere region.

In this phase, crossing over occurs early on when homologous  chromosomes pair up. This is where non-sister chromosomes exchange genetic information. This leads to an increase in genetic variation and allows new combinations of traits as DNA from both parents is inherited and put together.

Metaphase I

During Metaphase I, the homologous chromosome (still paired up) line up at the metaphase plate. The homologous pairs of chromosomes line up randomly, which is known as independent assortment. The maternal and paternal homologous pairs are sorted into the daughter cells independent of the other pairs. Spindle fibers then attach to the kinetochores of the homologous pairs.  These two kinetochores holding together the sister chromatids are attached to a different spindle fiber extending from a different pole.

Anaphase I

The homolgous pairs of chromosomes seperate, but the actual sister chromatids do not. The sister chromatids stay attached at the kinetochore. This means that one sister chromatid is pulled to one pole by the spindle fibers, while the other sister chromatid is pulled to the other. 

Telophase I and Cytokinesis 

The sister chromatids finish their movement to the poles, and each half of the cell has two sister chromatids in it. This marks the end of mitosis I, which is considered to be a reductional division.

After Telophase I, cytokinesis occurs, as the cytoplasm is divided. Two daughter cells with sister chromatids  within them are formed.