What is the difference between ICSI and IVF?

Regular in vitro fertilization involves taking an egg from the female and placing it in a petri dish in the laboratory and then incubating it with fairly large numbers of sperm—hundreds of thousands of sperm. If all goes well, one of those sperm will then fertilize the egg. ICSI or intracytoplasmic sperm injection involves going a step further, where an individual egg is isolated and individual sperm is selected and that sperm is then drawn up into a pipette, the pipette is inserted into the egg, and the sperm is deposited into the egg, and if all goes well then fertilization will occur resulting in the formation of an embryo. So ICSI is really critical from the world of male reproductive health. Even in the most severe cases of male infertility where only a handful of sperm may be available, we can use those individual sperm to help couples achieve pregnancies.