A number of factors can play a role in some couples' inability to conceive. In men, most issues are associated with vitality ...

In contrast, each egg cell, or ovum, is relatively large and non-motile. During fertilization, a spermatozoon and ovum unite to form a new diploid organism.

The female gamete is called an ovum or egg. The plural is ova. Ova are produced from germline cells in the ovaries. Ovaries contain immature ova at various stages of development. Each ova is ...

Most animals carry out sexual reproduction. Sexual reproduction involves the joining of two sex cells (gametes) – the sperm (male gamete) and the egg/ovum (female gamete).