Genetic testing before an embryo is implanted may be available for those using in vitro fertilization.

Until now, Dr. Kiessling's patients used in vitro fertilization, working with their own doctors.

The Camden County couple used in vitro fertilization to create the embryos.

However, some terrestrial arthropods do use external fertilization.

Consideration as to whether an animal (more specifically a vertebrate) uses internal or external fertilization is often dependent on the method of birth.

The species uses internal fertilization - the fertilized eggs undergo direct development.

Adults mate during the months of August and September using internal fertilization.

While they may have used internal fertilization, this has yet to be demonstrated.

Some fish species use internal fertilization and then disperse the developing eggs or give birth to live offspring.