Which of the following should be avoided in biological marriages ?
(a) A+ boy and A+ girl
(b) A+ boy and A- girl
(c) O+ boy and O+ girl
(d) O-boy and O- girl

Options

A. A+ boy and A+ girl
B. A+ boy and A- girl
C. O+ boy and O+ girl
D. O-boy and O- girl

Answer

To determine which biological marriage combination should be avoided, we need to analyze the Rh factor compatibility between the parents. The Rh factor is a significant aspect of blood compatibility and can affect pregnancy outcomes.

### Step-by-Step Solution:

1. **Understanding Rh Factor**: The Rh factor can be either positive (+) or negative (-). It is crucial to consider this factor in marriages, especially when planning for children.

2. **Analyzing Each Option**:
- **Option (a)**: A+ boy and A+ girl
- Both parents are Rh positive. This combination is generally safe as both can produce Rh positive offspring.
- **Option (b)**: A+ boy and A- girl
- The boy is Rh positive and the girl is Rh negative. If they have a child, there is a possibility that the child could be Rh positive. This can lead to complications if the mother’s body perceives the Rh positive fetus as foreign, potentially causing erythroblastosis fetalis.
- **Option (c)**: O+ boy and O+ girl
- Both parents are Rh positive. This combination is safe, similar to option (a).
- **Option (d)**: O- boy and O- girl
- Both parents are Rh negative. This combination is also safe as they can only have Rh negative children.

3. **Conclusion**: The combination that should be avoided is option (b) - A+ boy and A- girl, due to the risk of complications arising from Rh incompatibility.

### Final Answer:
**(b) A+ boy and A- girl should be avoided in biological marriages.**

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