**Core Concept**
Herpes simplex virus (HSV) infection during pregnancy is generally not considered to have a significant impact on fetal development compared to other teratogenic agents. However, neonatal herpes can occur if the baby is infected during delivery, but this is not directly related to the virus affecting fetal development in utero.

**Why the Correct Answer is Right**
Herpes simplex virus (HSV) primarily causes a mucocutaneous infection in the neonate, rather than a congenital anomaly. This is because HSV typically causes a localized infection at the time of delivery, rather than a systemic infection that affects fetal development. In contrast, other viruses like rubella can cause congenital rubella syndrome, which includes a range of developmental abnormalities.

**Why Each Wrong Option is Incorrect**
**Option B:** Rubella is a well-known teratogen that can cause congenital rubella syndrome, which includes deafness, cataracts, and heart defects. This makes it a significant risk for fetal development.
**Option C:** Alcohol exposure during pregnancy can cause fetal alcohol spectrum disorders (FASD), which includes a range of developmental and physical abnormalities.
**Option D:** Tetracycline is a broad-spectrum antibiotic that can inhibit bone growth and cause tooth discoloration in the fetus if taken during pregnancy.

**Clinical Pearl / High-Yield Fact**
It's essential to note that while herpes simplex virus is not typically a teratogen, it can still cause significant morbidity in the neonate if passed on during delivery. Pregnant women should be counselled on the risks of HSV transmission to their babies.

**✓ Correct Answer: A. Herpes**