Final answer:
A person with Klinefelter's syndrome (XXY) is more likely to have an X-linked disease like haemophilia than a person with Turner's syndrome (XO), because Klinefelter's individuals have two X chromosomes, one of which could carry a mutation causing haemophilia.
Step-by-step explanation:
A person with Klinefelter's syndrome, which is characterized by the presence of an additional X chromosome (genotype XXY), is more likely to have an X-linked disease like haemophilia compared to a person with Turner's syndrome, who has only a single X chromosome (genotype XO).
The reasoning behind this is that haemophilia is an X-linked recessive disorder. Hence, males (who have only one X chromosome) are more likely to exhibit the symptoms of the disorder when they inherit a gene with the mutation because they lack a second X chromosome that could carry a normal allele of the gene. Individuals with Klinefelter's syndrome are phenotypically male but have two X chromosomes in addition to their Y chromosome, making it possible for them to be affected by X-linked diseases if they inherit a mutated gene on one of the X chromosomes.
By contrast, Turner's syndrome individuals, who are phenotypically female, would require both X chromosomes to be affected for them to exhibit the recessive disorder, which is not possible in their case since they have only one X chromosome.