These twins are often not recognised as twins by the general public who often believe that twins always means children of the same sex. The fact that there may also be differences in growth at all stages may contribute to this, with the larger child assumed to be the older one.

When the fetus is in the womb the mother responds to the sex of her baby by providing the appropriate nutrients. When there are two babies of different sexes, they may receive the nutrients appropriate to the opposite sex. This may have future repercussions inasmuch as the girl may have more in common with dad and the boy may be more empathic and sensitive which may bring out protective feelings in the mother. However this does not necessarily always follow. Twins will differ in their characteristics.

Because girls tend to mature at a faster rate than boys, the girl may start by taking the dominant role in the pair becoming a second mum to her brother and what I have sometimes termed the boy’s ‘Social Secretary’ and because the boy may have developed his sensitive side, Mum too may see him as needing protection.

The girl twin is often the more verbal of the two, which may result in the boy resorting to physical means to resolve arguments which he has not the verbal skills to win. It may appear that the boy is in the wrong because the girl has used her tongue to upset the boy and he has simply reacted. However it must be remembered that the reverse can be the case and the boy may outshine the girl physically and intellectually.

Growth and puberty are genetically linked and brother and sister will not have an identical inheritance. The later developer, who may look like a younger brother or sister, is often treated as one by the twin and others and may feel some resentment and try to attract attention to themselves
in other ways.

It’s important to remember that boys from opposite sex pairs are just as masculine as any other boys, but tend not to be as macho. He is influenced by his sister just as much as she is by him. Playgroup or nursery on separate days will help them both to be themselves. Sons also benefit from doing things with dad without their sister, whilst mother and daughter have some time together on their own too.

For opposite-sex twins adolescence can be a testing time as girls tend to mature faster than boys. A brother who has enjoyed a close relationship with his sister may have his self-image badly shaken if she starts dating older boys and doesn’t want to be seen with her ‘little’ brother His sister’s bedroom becomes strictly private and confidences are shared with girlfriends. The twins’ ‘secret garden’ has a large KEEP OUT sign on the gate!

The boy may have doubts about his own masculinity and feel rejected and confused by his sister’s mood swings. Fathers have an important role in building up his confidence. A part-time Saturday or evening job can be a great ego booster – a bit of cash in the pocket and a feeling of being part of the adult world. If there is no regular job available neighbours may like their cars cleaned, some gardening done or may need a regular baby-sitter.

The girl also needs to feel that her parents approve of her and accept she is growing up. If mother and daughter can sometimes have outings together they will have opportunities to talk in a relaxed situation and advice can be given when asked for. This will help to lay the foundations of an adult relationship.

Separate secondary schools can help to avoid some of the problems. The twins will feel freer to mature at their own rate, develop their own interests and make their own friends without looking over their shoulders.

FURTHER READING: Twins and the Family available on the website.
Hidden Twins by Olivia Lousada