Daughters are a great blessing because Allah (SWT) has promised a place in paradise (Jannah) on bringing them up. The one who has 3 daughters or sisters, or 2 daughters or sisters and he brings them up properly and fears Allah (SWT) regarding their rights, then Paradise is made mandatory for him.
In some Ahadith, when the Prophet (SAW) mentioned the blessings of bringing up 3 daughters or sisters, somebody asked “What if someone has only 1 daughter?” The Prophet (SAW) mentioned the same prize for him as well, i-e a place in the paradise. Paradise would never be made mandatory for such people had daughters not been blessings of Allah (SWT).
This shows that daughters are indeed a source of blessing from Allah (SWT), therefore if a daughter is born in someone’s house, he should not be saddened by this, instead he should rejoice and thank Allah (SWT) for this blessing.
How can they be inferior when a place in paradise is being promise against them? Getting saddened by the birth of daughters was the practice of the Non-Believers (Kuffar) because before the Prophet (SAW) came, the Kuffar used to get saddened by the birth of daughters and used to consider them a burden as they would need to find someone for their daughters to marry. They were such animals that they used to bury their innocent daughters alive.
It is these blessed daughters that are the means for the existence of humanity, how can they be considered a curse, this is the act of the Non Believers. The Prophet (SAW) has called her a blessed woman who’s first child is a daughter. Therefore rejoice and smile when you hear about the birth of daughters and consider them a blessing for yourself.
Islam has given a very high status to daughters, therefore consider them a huge blessing of Allah (SWT). It is these daughters through whom Saints (Auliya Allah) are born and above all, our beloved Prophet (SAW), for whom this world was created, his family and bloodline was continued through his daughter.
If daughters were not a blessing then Allah (SWT) would never choose them to carry forward the bloodline of his most beloved Prophet (SAW). This shows that daughters are indeed a great blessing so do not consider them inferior. Sons bring Daughters in Law and Daughters bring Son in Law. Sometimes the son in law is so obedient that he surpasses daughters in serving his parents in law.