Now this is a very simple way to increase libido in women. According to a study, people experience an increase in their "dopamine" levels after looking at the photograph of their loved one for 30 seconds or more. Higher dopamine levels increase your desire to have sex. Let's now explore this window further to find out when was the best time.The egg once released have a lifespan of twelve (12)hours. The egg therefore, needs to be fertilized in this twelve- hour period for conception to occur. The sperm on the other hand can survive as much as 5 days in the reproductive duct.