Background: Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically.[2] By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious or recessive traits resulting from incestuous sexual relationships and consanguinity.

Inbreeding results in homozygosity, which can increase the chances of offspring being affected by deleterious or recessive traits.[3] This usually leads to at least temporarily decreased biological fitness of a population[4][5] (called inbreeding depression), which is its ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially referred to as inbred. The avoidance of expression of such deleterious recessive alleles caused by inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossing.[6][7] Crossbreeding between populations also often has positive effects on fitness-related traits,[8] but also sometimes leads to negative effects known as outbreeding depression. However increased homozygosity increases probability of fixing beneficial alleles and also slightly decreases probability of fixing deleterious alleles in population.[9] Inbreeding can result in purging of deleterious alleles from a population through purifying selection.[10][11][12]

Situation: Two farmers both had ten cattle each. Bill decided to interbreed his cattle, but James didn't because he knew about the consequences. Two years later Bill had 12 cattle and James had 30 healthy cattle.

Question: Which farmer used consanguinity to breed his cattle?
Answer: Bill

Situation: Two farmers both had ten cattle each. Bill decided to interbreed his cattle, but James didn't because he knew about the consequences. Two years later Bill had 12 cattle and James had 30 healthy cattle.

Question: Which farmer didn't use consanguinity to breed his cattle?
Answer: James

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill had 12 sick cattle and James had 30 healthy cattle.

Question: Which farmer lost more cows as a consequence of inbreeding?
Answer: Bill

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill had 12 sick cattle and James had 30 healthy cattle.

Question: Which farmer lost fewer cows as a consequence of inbreeding?
Answer: James

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill had 12 sick cattle and James had 30 healthy cattle.

Question: Which farmer's cattle were healthier than the other's?
Answer: James

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill had 12 sick cattle and James had 30 healthy cattle.

Question: Which farmer's cattle were less healthy than the other's?
Answer: Bill

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill's farm had 12 sick cattle and James' had 30 healthy cattle.

Question: Which farmer's cattle had more deleterious or recessive traits?
Answer: Bill's

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill's farm had 12 sick cattle and James' had 30 healthy cattle.

Question: Which farmer's cattle had fewer deleterious or recessive traits?
Answer: James'

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill's farm had 12 sick cattle and James' had 30 healthy cattle.

Question: Which farmer's cattle had fewer fitness-related traits?
Answer: Bill's

Situation: Two farmers both had ten cattle each. Bill decided to use inbreeding as a method to breed his cattle, but James didn't because he knew about the consequences. Two years later Bill's farm had 12 sick cattle and James' had 30 healthy cattle.

Question: Which farmer's cattle had more fitness-related traits?
Answer: James'