It is the question the world has which reasonably makes sense when marriage is the factor as opposed to having pre-marital sex. Reasonably? Yes, we can reason to do whatever and when found in trouble still in complete ignorance and destainable foolishness, justify the reason for doing it. Also notice that past tense was used for having the question because the use of the cow and milk analogy is archaic along with the one about purchasing a car without test driving it or buying a house without having the walk through and the like. Why? Because it isn't difficult to find sex as it once was. Men use to enjoy the chase and while still running he comes to the realization of his own foolishness. One use to believe this realization was his manhood. Why use to? Well, manhood is defined in different ways now and because in 7 years he will wonder if he still "has it." The "it" is called the "itch" and these days, women have it too.
There is no need in defining the "itch"; it is, after all the ways of the world having no parts of Christianity. Christians have said such things though now, it being closer to the coming of Christ, has been said in smaller circles. Or when coercion of an unwilling participant to have sex just to satisfy said itch; and again, these days men aren't always the one doing the aggressing. Still back to the subject matter, when you think about the question having better knowledge of the truth, it sounds stupid. Like saying dunderhead 15 times. That word starts not to make sense anymore. Who buys a cow when the milk is free?
Who? the farmer, that's who. If the milk is good but he has to go elsewhere besides his home to get it, why not buy the cow and get all the milk he desires? The farmer knows what to do with the cow and at the right time when to breed and then he uses the cow for food. You see there is a better analogy here once you realize who the farmer is.
Scripture discusses the farmer when sowing seed (James 5:7 AMP). He doesn't watch the seed. He knows that the good seed has been sown in good ground and at the due time will reap a good crop (Matthew 13:1-18 NIV). The faith used for this is through studying, experience, observation, and it being his profession. God is the farmer. We are good ground. The seed is the Word. Come on people!
The next time or when the time comes where the unrestrained individual starts rubbing or pulling on you and asking, "what are you saving it for?" Remember what you have been saved from. The farmer bought the cow (Galatians 3:13 AMP).