When a sperm fertilizes an egg within the female, it is known as internal fertilization. The advantages of internal fertilization are that the fertilized egg is protected from predators and harsh environments, thus ending in higher chances of survival. Also, there is a lesser chance of desiccation of gametes. Disadvantages of internal fertilization are that there are lesser number of offspring produced at a given time because it is sometimes difficult for the male and female to come into intimate contact. Additionally, the risk of sexually transmitted diseases also increases.