Genesis 6:4

There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.

1. There were some very tall people on the earth around the time of Noah.
2. Some of the very early men were mighty, honored and widely acclaimed.
3. The fame of people spread then just as it does now.
4. Children are the result of and a purpose for sexual relations.