How many eggs and sperm are required to create identical twins in humans?

Options

A. `2` eggs, `2` sperm
B. `2` egg, `2` sperm
C. `2` eggs, `1` sperm
D. `1` egg, `1` sperm

Answer

To determine how many eggs and sperm are required to create identical twins in humans, we can follow these steps:

### Step 1: Understand the Types of Twins
- There are two types of twins: monozygotic (identical) twins and dizygotic (fraternal) twins. Identical twins come from one zygote, while fraternal twins come from two separate zygotes.

**Hint:** Remember the difference between monozygotic and dizygotic twins.

### Step 2: Define Monozygotic Twins
- Identical twins, or monozygotic twins, occur when a single fertilized egg (zygote) splits into two embryos. This means they share the same genetic material.

**Hint:** Focus on the fact that monozygotic twins originate from one fertilized egg.

### Step 3: Identify Gametes Involved
- For the formation of a zygote, one sperm (male gamete) fertilizes one egg (female gamete).

**Hint:** Recall that fertilization involves one sperm and one egg.

### Step 4: Determine the Number of Eggs and Sperm
- Since identical twins come from one zygote, only one egg and one sperm are needed. After fertilization, the zygote can split into two, leading to the development of identical twins.

**Hint:** Think about how many gametes are involved in the creation of a single zygote.

### Step 5: Conclusion
- Therefore, to create identical twins, only **1 egg and 1 sperm** are required.

**Final Answer:** 1 egg and 1 sperm are required to create identical twins in humans.