This confuses me. I find it highly unlikely the average human shares more genes with a chimpanzee than another human and even more unlikely that siblings only share 50% of their genes.

probability estimates (statement is true):

• 99% genetic similarity to a chimpanzee = 75%
• 95% genetic similarity to a random human = a low nonzero number
• 50% genetic similarity to a sibling = 0%
• 95% genetic similarity to a random human given 99% genetic similarity to a chimp = 0%

I am going to research this.

EDIT: findings:

1. Researching an an actual number is exceeding difficult. About 50% of the pages are non-secular websites (this may be my non-optimized google searching). The rest are a mix between technical articles and articles formatted for the average human (average being living in a English speaking and developed nations).

2. 99% genetic similarity to a chimpanzee

Mostly correct. Estimates range between 95%^[1] and 98.8%^[2]

• 95% genetic similarity to a random human

Incorrect. Estimates are at 0.1%^[1]. I did not notice other numbers.

• 50% genetic similarity to a sibling

Incorrect as you stated it (comparing total gene dissimilarity). You might want to reword it since you were probably comparing what percentage of gene can be attributed to a parent.

[1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC129726/ [2] http://humanorigins.si.edu/evidence/genetics