Watch: why donating blood is so important
People from across the South East are joining calls from the NHS urging more men to donate blood.
There's a worry not enough male donors are coming forward which could create problems because their cells can be more effective in helping sick people.
Danielle Jinadu knows how important blood donations are.
The 23-year-old law student has the life-threatening genetic disorder sickle cell disease, and needs eight units of blood every six weeks.
Like all patients who receive multiple transfusions, Danielle relies on a safe and secure supply of blood, and male donors help ensure blood is always there.
Danielle, who is studying law at the University of Warwick, said:"For me, blood transfusions are literally the difference between life and death. Without blood transfusions I know I would not be here alive at 23 years old.
"The people that give blood are often the hidden heroes. I will never get to know their names but they are extraordinary."
The NHS is worried though because there's an imbalance in donations.
Last year, only 40% of new blood donors in our region were men.Until the end of November, almost 12,500 women started donating blood in the South East - compared to just over 8,500 men.
Ellie Hudson knows how important male donors are.
Her son Finley needed three specialist blood transfusion when he was born...
He is one of around 120 people in the UK with the condition Diamond-Blackfan anemia which means he cannot produce red blood cells.
The two-year old now has monthly transfusions at Maidstone hospital.
Ellie said: “He would go in once a year or so but since Finley was born he goes as regularly as he can. We are so thankful to everyone who donates, they really are lifesavers.”
The NHS wants 48% of its donations this year in the South East to be from men.
Mike Stredder, the head of donor recruitment for NHS Blood and Transplant, said:
"All our donors are amazing. But we need more men to start donating blood in the South East during the New Year. Men's blood can be used in extraordinary, lifesaving ways, but we don't have enough new male donors coming forward. This is not about recruiting as many donors as possible - it's about getting the right gender mix.
"If you can't find an appointment right away don't worry - your blood will do extraordinary things if you donate in a few weeks instead."