I wanted to know if you know anything about rulings on a woman doing an ultrasound in her pregnancy to find out the gender of the baby, is it haram because Allah stated in Surat Luqman,

"Verily the knowledge of the Hour is with Allah (alone). It is He Who sends down rain, and He Who knows what is in the wombs. Nor does any one know what it is that he will earn on the morrow: Nor does any one know in what land he is to die. Verily with Allah is full knowledge and He is acquainted (with all things)."[1]

As He (سبحانهُ وتعالى) said "what is in the wombs" I was a bit confused because many people do ultrasounds today for finding out their babies' gender. Is it haram because only Allah knows? If we try to find out, are we trying to do what He does?

It is not haraam to do the ultrasound test.[2] Allah's knowledge of what is in the wombs is absolute and our knowledge is very limited. This is just as Allah knows the future absolutely while our knowledge of the future (cycles of the moon, weather patterns, etc.) is limited.

References:

[1] [Qur’an 31:34]

[2] “Is knowing the sex of the baby part of the knowledge of the unseen” (http://islamqa.com/en/ref/12368/sex%20of%20the%20foetus)