Madonna is facing growing opposition over her plan to adopt another child from Malawi.
Children's charity Save the Children urged the singer to think again, while there were reports the family of the toddler she is seeking to remove from the impoverished African republic is fighting the adoption.
The 50-year-old star has filed papers in Malawi setting out her intention to adopt an orphan called Mercy James, who she hopes to take back to the US if a Malawi court approves the plan.
Madonna already has an adopted son from Malawi.
Questions were asked after she and then-husband Guy Ritchie took David Banda to their London home in 2006 while the child was 13 months old, and her latest quest for a sister for David has led to renewed criticism.
Mercy's grandmother hit out at the Material Girl star, who will reportedly travel to Malawi tomorrow to spend time with the girl and to launch proceedings to make the girl legally her daughter.
Lucy Chekechiwa, 61, told the Sun: "Why doesn't this singer pick other children? It is stealing. I want to go to court, I won't let her go."
Mercy has been living in a Malawi orphanage and Mrs Chekechiwa claimed it had been agreed the child would go to her when she reaches the age of six.
According to the paper, Mercy's 18-year-old mother died five days after her birth.
Meanwhile, Save the Children said orphans should be cared for by extended family in their home country and suggested international adoption can make matters worse.
