(Image by Thomas Breher from Pixabay)

The equal rights argument comes to the conclusion that all living members of the human species have human rights. If we categorise the preborn as non-persons, on the basis that they are, for example:

  • Dependent
  • Lack cognitive sophistication
  • Lack moral agency and the ability to make rational decisions
  • Nonconscious 
  • Or lack the capacities for any of the above 

We are forced to come to the conclusion that other born human beings are non-persons, too. Most people do not want to come to this conclusion. Ergo, human rights for all human beings and preborn humans are included in that. 

One claim that can come up in this general kind of discussion though is the claim that, though an embryo or foetus doesn’t have capacities like these, they have the potential to develop them because of the kind of thing they are (members of the human species) and that potentially having these capacities is what gives them dignity and value. I personally tend not to use this line of argument. For one thing, I think this line of argument can get pretty complicated quite easily. But it’s also not the case that every individual embryo or foetus actually does have this potential: ones that will be born with severe disabilities are not. What’s more, there are born people with severe cognitive disabilities whose bodies do not have the potential to develop these capacities: and their moral status – the value of their lives, of them – is not diminished because of this.

But whether you intend to bring up talk about potential capacities or not, potentiality can sometimes work its way into discussions about abortion. There’s one question in particular that sometimes throws me a bit: it seems so incredibly easy to answer, and when people don’t accept what seems to me like a very obvious response, I can be a bit taken aback. The question is ‘A sperm is going to become a human being one day, so does it have rights?’ 

To me the logic of this question, especially if it’s meant to be a serious objection, just isn’t intuitive. A sperm cell is not a human organism with the potential to grow into an adult human being.  To me it just seems like the question that stems from a lack of understanding about basic biology. And it probably often does. In this post, I’m going to do my best to give it a fair hearing anyway. In case you’re a pro-choice reader, and think this is a bit harsh – these are the kinds of things you sometimes hear. This is an extract from a blog post written by Monica Snyder, the executive director of Secular Pro-Life:

Here are some real examples of assertions people have made over the years:

Sperm are organisms

Gametes are organisms

Neurons are organisms

Skin cells are organisms

Literally all cells are organisms

Embryos are made of “non-living” cells […]

If an embryo is a human organism, so is snot. Or poop.

The idea “the zygote is the first stage of a human’s life cycle” is not supported

As Snyder points out, however, all these claims are flatly false. With regard to the claims most relevant to this post:

For any readers who genuinely don’t already know: human sperm and human ova (eggs) are gametes (sex cells). They are not organisms. They are haploid cells (typically have 23 chromosomes each) created through a process called meiosis. A human organism is formed through fertilization; the sperm enters the egg to create a diploid cell (typically 46 chromosomes). This cell is called the zygote and it now multiplies through mitosis. Fertilization is a specific event that marks the transition from multiple gametes to a single organism and from meiosis to mitosis. These are basic biological facts. Read more here.

As Snyder points out elsewhere, these basic facts are acknowledged in plenty of neutral sources. But what should you do if, despite this, someone still thinks that the sperm has potential to become a fully grown human adult? Where do you go from there? Thinking this through helped me better understand where pro-choice people who are concerned about this are coming from. Here’s what I think I’d ‘say’ to one of them. 

  1. The sperm and egg do not  transform and carry on their existences together as a zygote. 

The zygote is a new organism, a new entity, formed in fertilisation. This is important. The sperm does not ‘turn into’ a zygote, neither does the egg. Instead, when they combine, the result is a different kind of thing altogether: the sperm and egg were gametes with 23 chromosomes. If fertilisation does not occur, neither of them will start to multiply through mitosis and grow into a human baby. The zygote is a completely different kind of cell – the kind of cell that does this. It is the kind of thing that has the potential to develop into a human baby. The sperm and the egg are not – they simply do not have this potential; if they did, they would not be gametes. When they combine, they cease to be the kinds of things that they were – gametes – and are combined to form a new kind of thing – a zygote. There are no more gametes once the zygote is formed – the gametes, the sperm and the egg, aren’t there any more after this happens.

  1. The zygote is ‘more like a compound than a mixture’

One way of thinking about what’s going on is to think: egg + sperm = zygote, so the sperm becomes a zygote, or at least part of it, and everything that will happen to the zygote, everything it will become, will also happen to the sperm and the egg, will also be what they become.

This isn’t quite the right way of thinking about it, though it’s a good way of understanding how some mixtures work. If I add some milk to my tea, when I drink the mixture in my cup, the mixture is being drunk, and therefore the tea and the milk are being drunk, too. The milk doesn’t cease to be milk when it is added to tea, nor does the tea cease to be tea. But this is not how all combinations work. I remember doing Junior Certificate chemistry, and being told that a compound is a substance that is made up of more than one type of atom bonded together, whereas a mixture is a combination of two or more elements or compounds which have not reacted to bond together; which means that each part in the mixture retains its own properties. The tea is like a mixture.

But water and hydrogen peroxide are compounds: when two hydrogen atoms and one oxygen atom combine to form water, the resulting molecule has different properties to the atoms that made it. It has different potential, and different actual properties. Hydrogen peroxide is made of two hydrogen atoms bonded together with two oxygen atoms. It has completely different actual properties, and completely different potential properties. Neither are best understood as just being a mixture of hydrogen and oxygen.

The formation of the zygote out of a sperm and an egg is more like that of these compounds I learned about in Junior cert science than like my milky tea. My tea has the properties of the milk and the tea – they have not disappeared and been replaced by ‘milky tea’ a new substance that has different actual and potential properties. That is why we can say that the tea is being drunk and the milk is being drunk. 

But we cannot really say that I am drinking hydrogen and oxygen when I drink water – if I were doing that, I would be drinking ‘air’, I’d be drinking two gases. Hydrogen and oxygen do not have the same properties as water, even though water is formed when the two kinds of atoms combine in a particular way. Similarly, the zygote has the potential to survive long enough to grow into a blastocyst and implant into the uterine lining, and then keep on growing. But the sperm and egg do not. This is just part of what makes them what they are: gametes, not organisms. 

It makes as much sense to say that a sperm has the potential to become an adult human being as it does to say that oxygen can be used to slake thirst or be turned into ice cubes in the freezer and then put in drinks on a sunny afternoon.