Reproductive System

• production of sperm in Males

• production of eggs in Females

• continuation of species by creating babies

Do you have siblings? How many?

• more than 4 million babies born in the US each year

• 96% singleton births

• birth weight 4-8 pounds

• weight gives good chance for living outside the mother

• 2 babies

• occur about 3% of the time

• Birth weight of 2-5.5 pounds

• 2 types of twins: Identical & Fraternal

• one egg + one sperm

• egg divides into two and separates

• look exactly alike because they have exactly the same genetic makeup

Scott Kelly & Mark Kelly - twin astronauts

• 2 eggs + 2 sperm

• babies develop side by side

• may or may not look alike

• they do not have the same genetic makeup

6 sets of twins play basketball in Splendora

• 3 babies

• occur about .04% of the time

• birth weight 2.5 - 4 pounds

• typically 1 set of twins and a singleton

• can be identical

• 4 babies

• occur about .008% of the time

• birth weight 1.5 - 3 pounds

• makes it difficult to live outside mom without help

• 5 babies

• occur about .002% of the time

• birth weight less than 2 pounds

• 6 babies

• occur less than .001% of the time

• birth weight less than 1.5 pounds

• mom usually on fertility drugs

• makes more than one egg be released at a time

• 7 babies

• occurs less than .001% of the time

• birth weight 1 pound or less

• fertility drugs

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• 8 babies

• occurs less than .001% of the time

• birth weight 11 oz - 1.5 pounds

• fertility drugs

Octuplets born in Houston in 1998 - 1 died after a week only 11 ounces

• first called "Siamese Twins"

• first celebrity set worked on a circus and were from Thailand - called Siam at that time

• Married 2 women and fathered 21 children

• Died within 3 hours of each other

Have enough organs and limbs (legs and arms) to live separate lives

Some cannot be separated