**Core Concept**
Heteropaternal superfecundation is a rare phenomenon where two separate fertilizations occur in the same menstrual cycle, resulting in a twin pregnancy with different biological fathers.

**Why the Correct Answer is Right**
This occurs when a woman has intercourse with two different men within a short interval, usually 24-48 hours, during the same menstrual cycle. The first sperm fertilizes the egg, resulting in the formation of an embryo. Before the first embryo implants, the woman has intercourse with another man, and the second sperm fertilizes another egg, resulting in a second embryo. Both embryos then implant in the uterus, leading to a twin pregnancy with different biological fathers.

**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because heteropaternal superfecundation is a specific phenomenon that occurs when two separate fertilizations occur in the same menstrual cycle, resulting in a twin pregnancy with different biological fathers.

**Option B:**
This option is incorrect because dizygotic twinning is a separate phenomenon where two separate ova are released and fertilized by two separate sperm, resulting in fraternal twins.

**Clinical Pearl / High-Yield Fact**
It's essential to note that heteropaternal superfecundation is extremely rare, and the likelihood of it occurring is less than 1 in 50,000.

**Correct Answer: D. Heteropaternal superfecundation**