For Marieme and Ndeye, every birthday is an extra special milestone.
The conjoined twins weren't expected to live for more than a few days.
Their father brought them to the UK from Senegal in the hope of a better life.
Now they're settling into their new home in the Welsh capital, Cardiff.
(SOUNDBITE) (English) MARIEME AND NDEYE'S FATHER, IBRAHIMA NDIAYE, SAYING: "From what the consultant told me, from the strength of their feet and their hips, there is no reason that they couldn't walk.
There is no reason that they couldn't walk.
So all of this is just subject to the fact that if they are healthy enough.
So there is no reason for that not to happen." Hope that they will one day walk.
But any hope of them being separated has been dashed.
Doctors in London considered it only eight months ago.
But, scans have shown that although the girls have separate hearts and spines, they share a liver, bladder and digestive system.
(SOUNDBITE) (English) MARIEME AND NDEYE'S PAEDIATRICIAN, DR. GILLIAN BODY, SAYING: "As well as Mariame being dependent on Ndeye, Ndeye is actually dependent on Mariame for being alive.
So long-term, this actually sadly means that they can't be separated, on a very practical level." Ibrahima is pleased his daughters are developing well in the face of early expectations.
But he's realistic about the situation the girls are in and its potentially life-limiting complications.
(SOUNDBITE) (English) MARIEME AND NDEYE'S FATHER, IBRAHIMA NDIAYE, SAYING: "I know what I want for them - to happen - and I will do whatever possible for it to happen.
I've got the best team of people that can help it happen, but all of this is subject - is related - to their situation." Now three-years-old, the girls spend some of their time amongst other children their age at a playgroup.
In September, they'll reach their next big milestone - attending nursery five days days a week.