The United States has fallen into line with New Zealand, Australia and Britain by relaxing a decades-old rule that banned gay men from giving blood.
The US Food and Drug Administration has ruled that gay men can donate blood 12 months after their last sexual contact with another man.
This spells the end of a 30-year rule that saw gay men banned indefinitely from blood donation due to their increased risk of transmitting HIV, the virus that can lead to AIDS.
The change brings the United States into line with New Zealand, which reduced its deferral from five years to 12 months last December, after having shifted from a 10-year ban in 2009.
United Kingdom made the shift to 12-month deferrals in 2011, while Australian states adopted the change between 1996 and 2000.
Australia's change was based on studies evaluating more than eight million units of donated blood that showed no change in risk to the blood supply with use of the 12-month deferral.
These results, collected through the national blood surveillance system, were used to inform both the New Zealand and American law change.