Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: Sickle cell anemia is a genetic disease caused by an autosomal recessive gene. If each parent carries one sickle cell allele, what are the chances that their child will have sickle cell anemia?
one in four
25%.