A severe illness which affects the red blood cell count has

[BTGmoderatorDC]

A severe illness which affects the red blood cell count has been found to be hereditary. Fifty percent of those who are diagnosed with the illness have a parent who suffers from it. A known scientist has hypothesized that 50% of the children of carriers of the illness will also suffer from it at one point or another.

Which of the following, if true, would most weaken the conclusion drawn by the known scientist?


A. There are many diseases which are genetic, but few of them show a 100% chance of transferring to one's children.

B. Those suffering from the disease whose parents also suffer from it have, on average, one other sick sibling and three healthy siblings.

C. The illness, though serious, it treatable.

D. The average number of children per woman across the globe is less than 2.

E. If you have the illness, the chance that any specific grandchild of yours will suffer from it is 25 out of 100, considering no-one else in the grandchild's family has the disease.

OA B

Source: Economist Gmat

[deloitte247]

Premise: A severe illness that affects the red blood cell count has been found to be hereditary.

Conclusion: A known scientist has hypothesized that 50% of the children of carriers of the illness will also suffer from it at one point or another.

Option A - Incorrect
The argument in question is concerned about "a" severe illness (i.e a single unknown illness, not a generalization of all illness) that affects the red blood cell and is found to be hereditary. Of course, the claim portrayed by the option strengthens the argument because there are many diseases that are genetic but only a few of them are hereditary.

Option B - Correct
This option weakens the argument the most because 50% of the children of carriers of the illness will suffer from it, hence, we do not know if they have three healthy siblings. Therefore, this option is contrary to the argument.

Option C - Incorrect
We can't know if the illness is treatable because no record of treatment was stated in the passage.

Option D - Incorrect
This option is not in accordance with the argument as the average number of children per woman wasn't revealed.

Option E - Incorrect
In line with the passage, 50% of the children of carriers of the illness will also suffer from it at one point or another. We only know about the children of the carriers of the illness and not grandchildren, and as such, we can't predict the future based on this.


Thank You
<i class="em em-v"></i>