**Question:** Appropriate material for antenatal diagnosis of genetic disorders includes all the following except:

A. Blood samples from the pregnant woman or the fetus
B. Amniotic fluid samples
C. Umbilical cord blood samples
D. Placental tissue samples

**Core Concept:**
Antenatal diagnosis is a diagnostic procedure performed during pregnancy to identify potential genetic disorders or abnormalities in the fetus before birth. The available materials for this purpose include samples from the pregnant woman (blood), the fetus (amniotic fluid, umbilical cord blood, and placental tissue), and the placenta. Each sample provides different information about the fetus's genetic makeup and overall health status.

**Why the Correct Answer is Right:**
The correct answer, D. Placental tissue samples, is excluded because placenta samples primarily assess the mother's immune response and do not directly provide information about the fetus's genetic makeup. This makes them less suitable for detecting genetic disorders in the fetus compared to other sampling methods.

**Why Each Wrong Option is Incorrect:**
A. Blood samples from the pregnant woman or the fetus (Answer) - Blood samples provide information about the mother's immune response and can reveal abnormalities in the fetus.
B. Amniotic fluid samples - Amniotic fluid samples are commonly used to evaluate chromosomal abnormalities, structural anomalies, and other genetic disorders in the fetus.
C. Umbilical cord blood samples - Similar to blood samples, umbilical cord blood samples offer information about the fetus and can detect genetic disorders.

**Clinical Pearl:**
The correct options (A, B, and C) are essential for antenatal diagnosis, as they provide direct information about the fetus's genetic makeup and overall health status. In contrast, placenta samples are mainly useful for assessing the mother's immune response and do not directly address genetic disorders in the fetus.