Blaming women for giving birth to daughters is scientifically incorrect and socially unjust.
Human sex is determined by sex chromosomes:

Females have XX chromosomes

Males have XY chromosomes

A child inherits one sex chromosome from each parent:

The mother always contributes an X chromosome (since she only has X)

The father can contribute either an X or a Y:

X from father + X from mother = girl (XX)

Y from father + X from mother = boy (XY)

Therefore, it is the father’s sperm that determines the sex of the child, not the mother.