As for cages themselves, an ordinary citizen who kept dogs in similar conditions for their entire lives would risk prosecution for cruelty. A pig producer who keeps an animal of comparable intelligence in this manner, however, is more likely to be rewarded with a tax concession or, in some countries, a direct government subsidy.

Probability is the guide of life, and of death, too.

What one generation finds ridiculous, the next accepts; and the third shudders when it looks back on what the first did.

When the death of a disabled infant will lead to the birth of another infant with better prospects of a happy life, the total amount of happiness will be greater if the disabled infant is killed. The loss of happy life for the first infant is outweighed by the gain of happier life for the second. Therefore, if killing the hemophiliac infant has no adverse effect on others, it would, according to the total view, be right to kill him.

Sci-fi is often a metaphor. I think it's more the themes and questions that science fiction raises rather than the exact predictions that should guide us.

My view is different from this, only to the extent that if a decision is taken, by the parents and doctors, that it is better that a baby should die, I believe it should be possible to carry out that decision, not only by withholding or withdrawing life-support - which can lead to the baby dying slowly from dehydration or from an infection - but also by taking active steps to end the baby's life swiftly and humanely.

Even in the era of AIDS, sex raises no unique moral issues at all. Decisions about sex may involve considerations about honesty, concern for others, prudence, and so on, but there is nothing special about sex in this respect, for the same could be said of decisions about driving a car. (In fact, the moral issues raised by driving a car, both from an environmental and from a safety point of view, are much more serious than those raised by sex.)