Generally, strict liability products laws will hold manufacturers responsible for any consumer injuries that occur from using their products. However, products liability cases are not always governed by strict liability, nor are they always quite so straightforward in terms of liability. It is often the case that certain dangerous medical conditions and/or side effects are not linked to certain products or drugs until years after the product exposure or use has occurred. For instance, a childhood medication may not affect a child's health until he or she is an adult, or the link between the medication and a serious medical condition may not be made until twenty years after the fact. Another common example is exposure or use of a product by a pregnant consumer. If using the product had a negative effect on the developing fetus of the pregnant consumer, then the medical condition or side effect in question may not be discovered for months or even years. In these cases, it may be more difficult to prove causation, in terms of a manufacturer's responsibility for alleged injuries caused by the product.