Okay, so, I’m just going to hope you’re old enough for this not to be weird and you can always ask your parents about this!
But basically, there’s cell called a sperm. A sperm is the make “gamete” or sex cell. A woman has this thing inside her body called an egg cell, or ovum. It is a reproductive cell in oogamous organisms. The egg cell is typically not capable of active movement, and it is much larger than the motile sperm cells. So, sperm + egg = zygote. The formation process is usually called “fertilization”.
If you want a more direct answer, go to the Urban dictionary and just type your question in.
In this case, the only source of hydrogen is in the 6 molecules of water, therefore, the atoms of hydrogen, by applying stoichiometry with the Avogadro's number is:
