You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Kenya

Context:
Kenya won several medals during the Beijing Olympics, six gold, four silver and four bronze, making it Africa's most successful nation in the 2008 Olympics. New athletes gained attention, such as Pamela Jelimo, the women's 800m gold medalist who went ahead to win the IAAF Golden League jackpot, and Samuel Wanjiru who won the men's marathon. Retired Olympic and Commonwealth Games champion Kipchoge Keino helped usher in Kenya's ongoing distance dynasty in the 1970s and was followed by Commonwealth Champion Henry Rono's spectacular string of world record performances. Lately, there has been controversy in Kenyan athletics circles, with the defection of a number of Kenyan athletes to represent other countries, chiefly Bahrain and Qatar. The Kenyan Ministry of Sports has tried to stop the defections, but they have continued anyway, with Bernard Lagat the latest, choosing to represent the United States. Most of these defections occur because of economic or financial factors. Some elite Kenyan runners who cannot qualify for their country's strong national team find it easier to qualify by running for other countries.[citation needed]

Question:
Why has there been controversy in Kenyan athletics?

the defection of a number of Kenyan athletes to represent other countries