Who's the daddy?

In March 2016, newspapers around the world reported on a set of twins born in Vietnam to different fathers. This rare occurrence is known as 'heteropaternal superfecundation'.

In this instance, investigations began when relatives of the twins (now two years old) noticed that there were significant differences in their appearance. DNA testing confirmed their suspicions.

Parental responsibility

In this jurisdiction, 'parental responsibility' is defined in section 3 of the Children Act 1989 as 'all the rights, duties, powers, responsibilities, and authority which by law a parent of a child has in relation to the child and [their] property'. This includes the right to have contact with one's child, the right to make decisions as regards the child's upbringing (such as in matters concerning health and education), and the obligation to support a child financially and provide a roof over their head.

The notion of parental responsibility carries with it the ideology that both parents are equals with respect to the child. This is particularly important in the case of family breakdown so that the 'non-resident parent' does not feel their role is in any way diminished. Moreover, it is important for the child to understand that their parents are equals in the eyes of the law, and that each parent therefore has the same legal rights and responsibilities towards that child.

A mother (whether married
or unmarried) automatically
has parental responsibility from the birth of her child. A father
who is married to the child's mother at the time of the birth automatically acquires parental responsibility. Where the parents are not married at the time of birth, a father of a child born after 1 December 2003
can acquire parental responsibility by:

• Jointly registering the child's birth with the mother;

• Entering into a parental responsibility agreement with the mother; or

• Applying to the court for a parental responsibility order.

A father who subsequently marries the child's mother will also acquire parental responsibility but will need to lodge a registration form with the local registry office.

A father of a child born before 1 December 2003 can re-register the child's birth to confer parental responsibility upon himself and can do so either with the mother present or by formal agreement with the mother.

Crucially, a father who does not have parental responsibility for a child still has a duty to support that child financially.

Bi-paternal twins

Heteropaternal superfecundation can arise where a woman has sexual intercourse with two different men during the same ovulation period, resulting in the fertilisation of two eggs with the sperm from both men. Both sexual encounters would have to be very close in timing - even a matter of hours apart.

There have been only a
handful of reported legal cases involving heteropaternal superfecundation, the most recent occurring in New Jersey
in 2015. In that case, the mother sought child maintenance for both twins but the court ruled that the respondent father only had to pay child maintenance for one of the children as DNA testing proved that he was not biologically related to the other twin. The mother's claim for child support for the sibling twin was dismissed.

Legally, therefore, if the father was married to the mother at the time of birth, it would appear that in this jurisdiction he would have parental responsibility for both children, regardless of whether both children were biologically his. This would remain the case until it was proven otherwise (e.g. by DNA evidence to the contrary).

This gives rise to a highly unusual situation. Not only would the twins actually be half-siblings but the father would need to give careful consideration to whether he chose to be responsible for both children (which he may have been raising as his own for many years) when one child was not in fact biologically related to him. There is also the potential for considerable psychological damage for the child whose biological father is not in the picture at all.

While the eventuality of bi-paternal twins is extremely rare, it does remind us of the
law surrounding parental responsibility and, importantly, the duty to financially support
a child. Of course, countless
cases of heteropaternal superfecundation have probably gone unreported, or indeed unnoticed. It does, however, present an interesting legal conundrum should the truth
ever come to light. SJ

Carla Ditz is an associate at Family Law in Partnership